CN1084800C - Manufacture of two-way shape memory devices - Google Patents

Manufacture of two-way shape memory devices Download PDF

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CN1084800C
CN1084800C CN97182128A CN97182128A CN1084800C CN 1084800 C CN1084800 C CN 1084800C CN 97182128 A CN97182128 A CN 97182128A CN 97182128 A CN97182128 A CN 97182128A CN 1084800 C CN1084800 C CN 1084800C
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diameter
time
alloy
temperature
wire rod
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CN1253596A (en
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J·弗罗门布里特
N·布迪基南
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Litana Ltd
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Abstract

The present invention provides a method for manufacturing double-pass shape memory alloy and a device of double-pass shape memory alloy. The method can reversibly adjust characteristic transition temperature and the direction of the double-pass shape memory effect at the final manufacture stage.

Description

The manufacture method of two-way shape memory alloy and device
Invention field
Present invention relates in general to shape memory alloy (SMA), be temperature when changing, can be from the alloy of a kind of transfer of shapes, more specifically for the shape of another kind of " having stored memory ", the present invention relates to a kind of SMA of Ni-Ti base, be also referred to as too Nore (Nitinol) alloy of Buddhist nun.
Background of invention
Many metal alloys all have the ability that changes himself shape when temperature changes.This SMA can pass through a kind of reversible transition, and soft relatively and deformable martensitic state becomes material and has superelastic properties and hard relatively austenitic state by material.Thisly will be known as " austenitic transformation " in this article to the transformation of austenitic state, and another kind ofly be called " martensitic transformation " in this article to the transformation of martensitic state by austenitic state by martensitic state.Described austenitic transformation appears in a certain temperature range, and this temperature is than the temperature height that takes a turn for the worse and become.This means that in case change austenitic state into, even it is cooled to below the beginning temperature of austenitic transformation, but as long as temperature is higher than Ms (martensite start) point, SMA just will keep original state.
The special SMA of one class is the alloy-NiTi alloy of nickel and titanium.The NiTi alloy has been widely used in medical treatment and other field.SMA, the application of particularly a kind of NiTi base alloy in medical field is at United States Patent (USP) 4665906,5067957, and european patent application 143580 is introduced in many patents such as United States Patent (USP) 4820298.
For the application in medical treatment, require alloy to carry out austenitic transformation usually a scope narrow, that determine very much.For example, a kind of round trip SMA type blood vessel stent, as at publication number be described in 625153 the european patent application, when under body temperature, being martensitic state typically, put into body, through heating, just be transformed into austenitic state then, and when being cooled to body temperature, still keep austenitic state.Be understandable that,, will cause damage tissue on every side if it is too high to make SMA change the required Heating temperature of austenitic state into by martensitic state, thus undesirable.So, it is desirable to, require austenitic transformation to begin, and the temperature range of its transformation can not cause damage owing to excessively heating up to tissue in the temperature that is higher than the body temperature several years.
WO8910421-A discloses a kind of method that the physical and mechanical property of Ni-Ti alloy with shape memory effect is controlled, and comprises the steps:
-under 300-950 ℃ temperature, annealed 5 minutes to 2 hours
-carry out the cold working that deflection is 6-60%
-member is processed into desired shape
-under 400-600 ℃ the selected temperature of giving memory, heat-treat
-and cooling
Summary of the invention
An object of the present invention is to provide the method for a kind of NiTi of processing base alloy, obtaining a kind of alloy with double process shape-memory effect (SME), this alloy have can reversible adjustment the feature transition temperature.
More specifically, an object of the present invention is to provide a kind of so repeatedly method of the acquisition round trip SME of circulation " training " that do not require, to obtain round trip SME.
Another object of the present invention provides a kind of method that obtains round trip SME, and wherein, this SME in a very narrow temperature range austenitic transformation takes place.
Method of the present invention relates to two aspects.Its one side, this paper is expressed as it " described first aspect " sometimes, and described method provides a kind of austenite and martensitic transformation direction by the alloy that direction determined in controlled transformation that martensitic state carried out.Another aspect of the present invention, this paper is expressed as it " described second aspect " sometimes, and described method obtains a kind of alloy with austenite or martensitic transformation direction, but described direction is with irrelevant in the distortion that martensitic state carried out.
In below the description and claim, term " NiTi alloy " is used to refer to and a kind ofly mainly comprises nickel and titanium atom but also can contain the alloy of other metal of trace.Typical NiTi alloy has following empirical formula:
Ni lTi mA n
Wherein, A represents Ni, Cu, Fe, Cr or V
L, m and n represent the ratio of atoms metal in the alloy, l, the value of m and n is about respectively:
l＝0.5
m＝0.5-n
N=0.003 to 0.02
According to the present invention, a kind of treatment process with initial NiTi alloy of original shape is provided, to obtain a kind of alloy with net shape, under described net shape, this alloy shows double process shape-memory effect (SME), thereby it has austenite remember condition that represents relevant austenite shape and the martensite remember condition that represents relevant martensite shape respectively, and the step that described method comprises is:
(a) by measuring the difference between As and Af, test initial NiTi alloy, so that the interior tissue of described alloy is estimated;
(b) according to the result that obtains in (a), described initial NiTi alloy is carried out the thermal treatment first time, so that obtain to have the alloy of the essentially identical initial internal tissue of unordered dislocation desity;
(c) described alloy is carried out thermal-mechanical treatment (TMT), when comprising the described alloy of heating, it is carried out viscous deformation (for example warm-rolling system or warm drawing), so that during dynamic time effect is handled, (carry out ageing treatment in the cooling (depressing) that heats up), obtain a kind of polygon subgrain dislocation structure that is distributed with precipitated phase;
(d) if the distortion in the step (c) fails to obtain net shape, then described alloy is carried out intermediate heat treatment one time, finish a circulation that forms metacrystalline dislocation structure;
(e) repeating step (c) and (d) is until producing described net shape; And
(f) described alloy is carried out final thermal treatment and memory processing.
Described TMT carries out in an one step sometimes, if but the overall strain value surpass when causing the threshold value that forms pre-crackle (crackle is given birth to nuclear) in the alloy, what be necessary occasionally carries out in several steps.Generally when described alloy being heated to the temperature of about 0.3-0.6Tm (Tm is a fusing point, ° K of unit), carry out TMT.
In according to one embodiment of present invention, the step that described method comprises is:
(a) sample of initial NiTi alloy is heated to about 450-550 ℃ temperature, is incubated about 0.5-2.5 hour, then, the As of working sample and the temperature gap of Af;
(b) according to the difference of As that obtains of institute and Af in the step (a), described initial NiTi alloy is carried out the thermal treatment first time, division is as follows:
-as this difference less than about 7 ℃, then alloy is heated to about 450-500 ℃ temperature, and the insulation about 0.5-1.0 hour;
-as this difference greater than about 7 ℃, then alloy is heated to about 510-550 ℃ temperature, and kept about 1.0-2.5 hour;
(c) described alloy is carried out thermal-mechanical treatment, comprise that the part that occurs distortion in the described alloy is carried out inside is heated to temperature while of about 250-550 ℃, with less than 5 seconds -1Strain rate to its viscous deformation in addition, the deflection of this step is less than 55%, preferably less than 40%;
(d) if the distortion in the step (c) fails to obtain net shape, then described alloy is carried out intermediate heat treatment one time about 500-550 ℃ temperature, about 0.5-2 of time hour, then, repeating step (c) again; And
(e) described alloy is carried out once final thermal treatment and once memory processing.
The details of final thermal treatment and memory processing described aspect first with described second aspect in different.Aspect first, this processing comprises described:
The shape that will represent when (i) described alloy being processed into it being in austenitic state,
(ii) described alloy is carried out polygonization thermal treatment,, carry out solution treatment then, separate out with the dislocation of avoiding not arranging, and dislocation is arranged again, afterwards, carry out ageing treatment so that unordered dislocation is arranged.
(iii) described alloy is out of shape, so that it has a kind of adjustment shape, and it is handled, so that described austenitic state is remembered, be shaped as this austenitic state at above-mentioned (i) interalloy, and a kind of martensitic state remembered, under this state, the martensite shape of alloy has the intermediate deformation degree between between austenite shape and described adjustment shape.
Preferably, the step of described first aspect (ii) and (iii) comprises:
(ii) described alloy is carried out polygonization thermal treatment at about 450-550 ℃, about 0.5-1.5 of time hour, then, about 600-800 ℃ solution treatment about 2-50 minute, afterwards, and at about 350-500 ℃, the about 0.15-2.5 of ageing treatment hour, and
(iii) described alloy is out of shape, so that it has a kind of adjustment shape, described distortion is less than about 15%, and preferably less than 7%, distortion is carried out under temperature T, and this temperature satisfies following formula
T＜Ms+30℃
Wherein Ms is a Ms (martensite start) point, afterwards, described alloy is heated to the temperature of the austenitic transformation end of a period that is equal to or higher than alloy.
Should be noted that,, also need this circulation primary of repetition or repeatedly sometimes although usually the distortion circulation of above-mentioned steps in (iii) is just enough.
In aspect described second, final thermal treatment and memory are handled and are comprised:
(i) described alloy is processed into certain shape, but be not its when being in austenitic state with the shape of showing,
(ii) described alloy is at first heat-treated, then, carries out polygonization and solution treatment, be afterwards, randomly carry out ageing treatment,
When (iii) described Alloy Forming being in austenitic state for it with the shape of showing,
(iv) described alloy is carried out a memorize thermal treatment and an ageing treatment;
Thereby, alloy after treatment can be remembered a kind of austenitic state, under this state, alloy have above-mentioned (iii) in its austenite shape of showing, and can remember a kind of martensitic state, under this state, the martensite shape that alloy had is a kind of the have shape that is processed in above-mentioned (i) and shape of the intermediate deformation degree between the austenitic shape.
In the embodiment preferred aspect described, step (ii) and (iv) comprises:
(ii) under about 450-500 ℃, described alloy is heat-treated, and the time is about 0.5-2 hour, then, at about 600-800 ℃, described alloy is carried out polygonization and solution treatment, about 2-50 of time minute, afterwards, at about 350-500 ℃, described alloy is carried out ageing treatment, about 0-2 of time hour
(iv) at about 500-600 ℃, described alloy is carried out a memorize thermal treatment, the time surpasses about 10 minutes, then, at about 350-500 ℃ described alloy is carried out ageing treatment, about 0.15-2.5 of time hour.
After the processing in carrying out described first and described second embodiment, Af is about 10-60 ℃.In order to improve Af and As, can carry out timeliness thermal treatment to described alloy at about 350-500 ℃ afterwards.In order to reduce Af and As, can carry out a solution treatment to described alloy at about 510-800 ℃ afterwards.
Carry out local timeliness or solution treatment by the different sites to alloy, described alloy will have different austenite transformation temperatures.For example, for the stent in the medical treatment, require its different position to have different austenites and/or martensite transformation temperature sometimes.
Adopt aforesaid method, just can prepare SMA with various uses.Specific examples comprises medical device, for example various orthopedic devices, tooth root implantation piece, medical stent, intrauterine implantation piece, and non-medical device, for example pipe fitting joint.Prepare the method for this class medical device and adopt the device of this method preparation also to constitute one aspect of the present invention.
The accompanying drawing summary
Fig. 1 in the accompanying drawing shows under the different aging temps, the relation between Af and the aging time.
Detailed Description Of The Invention
In various medical use, the temperature range that the austenite transformation takes place is very crucial. Institute addresses An implementation be for example at being remembered by the round trip shape described in the european patent application 626153 Recall the medical stent that alloy (SMA) is made. Under body temperature, this shape memory (SM) device is put into pipe. Then, it is heated, in order to taking place, austenite changes, In case after the heating, described device still keeps austenitic state under body temperature, and to the wall of pipe Play a supportive role. This SM device is designed, so that the starting point that austenite changes occurs In the temperature that is equal to or higher than 40 ℃, yet, it should be noted that the generation austenite changes Temperature range should be narrow, because if temperature range is big, then excessive heating meeting is to causing tissue damage. And the narrow temperature scope generally can also be guaranteed to change more quickly the austenite shape into by martensitic state Attitude.
In the following description, sometimes will specifically have narrow austenite in conjunction with it in preparation and change model The present invention is described in application on the medical SM device that encloses, yet, it should be noted, this Invention is not limited only to this, and the present invention only is one for the preparation of medical stent Individual exemplary embodiment.
According to the present invention, initial NiTi alloy typically by manufacturer with wire rod or bar form Provide, at first the difference of the As of alloy and Af is measured. For this reason, need to get next little Alloy sample. Afterwards, according to the difference of As and Af, to described alloy, such as wire rod or bar Carry out the heat treatment first time.
After for the first time heat treatment, described alloy is carried out thermal-mechanical treatment (TMT), its In, alloy heats and mechanically deform simultaneously. In the method for the manufacture of medical SM device In, described mechanically deform generally comprises the change of alloy shape, becomes from initial wire rod or bar Web, band, etc.; Perhaps, make described wire rod or bar become the littler wire rod of diameter or bar. For the SME (SME) that keeps alloy, deformation extent total during the TMT should be little In 55%, preferably less than 40%. When desired final distortion total amount surpasses 55%, need Implement TMT in two steps, therebetween intermediate heat-treatment once also.
Thermal-mechanical treatment for example, can be: described alloy is being processed be used as medical treatment It is warm-rolling system during stent; Described alloy is being processed plant as orthopedic tooth root It is warm drawing when entering device; Deng, when warm-rolling system or warm drawing, typically with described alloy heating Temperature (Tm is fusing point, ° K of unit) to about 0.3-0.6Tm. The heating of crushed element must Must adopt electrostimulation, for example at about 500-2000A/cm2Current density under carry out. This A big advantage of processing is except causing mechanically deform, also can be to having the presplitting of high dislocation density Heat in the line district, and reason is that this pre-cracked zone resistance is relatively high, thereby can send out at these points It is selective overheated and cause pre-cracked zone to heat up to give birth to. And, the electro photoluminescence under above-mentioned current density Temperature TMT processes and accelerates dislocation reaction, thereby forms a kind of perfect dislocation subcrystalline structure. This Outward, the heating current dynamic time effect process that can cause separating out second-phase at subgrain dislocation cell wall is sent out Give birth to. This structure makes the temperature interval of the Af-As of marmem when austenite changes non-Often narrow, and make it have many other advantageous properties described below.
In the warm-rolling system of electro photoluminescence, when current density is down to 500A/cm2Below, perhaps the strain rate of distortion is higher than about 5 seconds-1The time, the increase of unordered dislocation density will occur, thereby reduce The perfect degree of subcrystalline structure for making the Af-As interval narrow, requires subcrystalline structure to the greatest extent can Can be perfect. Correspondingly, the increase of unordered dislocation density means the increasing at Af-As interval. For example, as the about 400A/cm of current density2, perhaps strain rate is about 8 seconds-1The time, final heat place Af-As interval after the reason will reach about 10-12 ℃. In addition, current density is increased to about 2000A/cm2More than can cause the generation of recrystallization, this will hinder the necessary subgrain that precipitated phase is arranged at cell wall Grain born of the same parents' formation.
Memorize is processed and is comprised a set-up procedure, and wherein, the micro-variations in the alloy can reach " memory " namely is in the shape of martensitic state in two kinds of shapes that alloy will represent between the operating period (" martensite shape ") and be in the shape (" austenite shape ") of austenitic state.
According to described first aspect, described alloy is processed into a kind of its is in austenitic state The time shape that will represent, for example, with regard to stent, this comprises alloy is wrapped in one On the individual axle that has with the stent same diameter that is in austenitic state. Then, allusion quotation Type ground places described alloy in the stove of sky always or inert atmosphere, in stove, at first to described Alloy carries out the polygonization of memorize and interior tissue to be processed, and the about 450-550 of temperature ℃, the time approximately 0.5-1.5 hour, be heated to again afterwards about 600-800 ℃, about 2-50 of time minute. After In this heating process of face, the solution treatment that described alloy generation dislocation rearranges, solid solution place After the reason, dislocation is able to freedom, subsequently, under about 350-500 ℃ temperature, described alloy is advanced The Ageing Treatment that row is final, the time is about 0.15-2.5 hour.
The result of above-mentioned processing has formed a kind of subgrain group of giving several specific characters of described alloy Knit, first austenite transformation temperature, Af can be investigated the scope at 10-60 ℃, and Af The interval of-As is very narrow, about 1-5 ℃.
Low Af can carry out solid solution place by alloy under about 510-800 ℃ temperature if beg to surrender Reason. In order to obtain desired Af, all can be controlled temperature and aging time. For example, If after the final heat treatment, the Buddhist nun is about 45 ℃ of the As of Nore alloy too, and Af is about 48 ℃, then 640 After ℃ carrying out 5 minutes solution treatment, As and Af are down to respectively about 23 ℃ and 27 ℃; 640 ℃ solution treatment is after 10 minutes, and As and Af are down to respectively 11 ℃ and 15 ℃.
In order to improve Af, can carry out Ageing Treatment at about 350-500 ℃ temperature alloy, with Sample in order to obtain desired Af, can be controlled temperature and aging time. For example, This point obtains explanation in Fig. 1, Fig. 1 showed 640 ℃ of solution treatment after 20 minutes, Aging time under two kinds of different temperatures (380 ℃ and 480 ℃) and obtain relation between Af. As seen, such as, the Af that obtained in 100 minutes 380 ℃ of lower Ageing Treatment is approximately 40 ℃, and only just can obtain identical Af value in about 40 minutes 480 ℃ of lower Ageing Treatment. The As that timeliness obtained in about 80 minutes under about 450 ℃ temperature is about 46 ℃, and Af about 49 ℃ (not shown in figure 1).
Unique characteristics of method of the present invention are that round trip SME is only by one The distortion circulation is just brought out and is formed. Described of the present invention aspect first, this can by Under T＜Ms+30 ℃ the temperature, described alloy deformation is become a kind of adjustment shape, afterwards again heating Temperature to the Af that is equal to or higher than alloy realizes. Described distortion should be less than 15%, and Preferably less than 7%. Deflection is higher than 15% will affect the interior tissue of material, and cause Ovshinsky The shape memory of body state is completely or partially lost. Deflection will between 7% and 15% Only has this illeffects of part. The Ma Shi that alloy represents after the above-mentioned set-up procedure of process The shape memory of body is a kind of intermediate shape between between austenite shape memory and adjustment shape. Direction phase in the direction of round trip SME after this memorize is processed and the distortion of martensitic state Unanimously. For example, if the distortion under the martensitic state causes diameter to reduce, then be in martensite The diameter of the alloy of state also will be less than the alloy diameter that is in austenitic state, otherwise and also So.
Usually, allow to the feature transition temperature with according to the method for described first aspect After fabrication stage the direction of round trip SME is carried out reversible adjustment.
Final memorize is according to a second aspect of the invention processed, and can needn't adopt finally Be out of shape and obtain round trip SME under the condition of bringing out round trip SME. When indirectly SME occurs, This effect is also uncertain. Described second aspect can be used for, and for example, has this of round trip SME In the manufacturing of Teng Te fixed die, and following description will be referred to this specific embodiment. Be 2R with NiTi band or wire rod at diameter1Axle on twine, fetter and put into a vacuum drying oven, Kept about 0.5-2.0 hour result, the generation interior tissue under about 450-550 ℃ the temperature The formation texture of just fighting. Similar to the above, afterwards, under 600-800 ℃ temperature, to institute State alloy and carry out solution treatment and tissue improvement processing, time 2-50 minute, then, 350-500 ℃ of lower Ageing Treatment, the time is 0-2.5 hour. Afterwards, described band or wire rod are twined again Be 2R around diameter2Axle on, this diameter is that stent will when being in austenitic state The diameter of showing afterwards, at 500-600 ℃, carries out a memorize and processes, and the time surpasses 10 Minute, and carry out Ageing Treatment at 350-500 ℃, the time is 0.15-2.5 hour. If should The strain stress of processingProcess＝1/2W(1/R 2-1/R 1)＜0 (W representative: the diameter the when thickness during band or wire rod), cooling period then, the corresponding strain stress of round trip SMEtw＝1/2W(1/R tw-1/R 2)＞0 (2R twDiameter when referring to stent and being in martensitic state), vice versa. This One result who processes is that the temperature range of austenite transformation is very narrow, Af-As=1-5 ℃, and, Might change Af between 10-60 ℃, this and top result are similar.
The consistent or phase of deformation direction when the round trip SME in the cooling can be with martensitic state Instead. If R2Greater than R1, and RtwLess than R2, described device will shrink when then cooling off. As Fruit R2Less than O, i.e. back-flexing, and R2Greater than Rtw, described device will expand when then cooling off Greatly.
At last, to be that alloy after being shaped has very high anti-for another result of method of the present invention The ability of spot corrosion and hydrogen embrittlement in Biomedia, because chloride ion content is higher, may go out Existing spot corrosion and hydrogen embrittlement.
Now, the invention will be further described by several specific embodiments.
The preparation of embodiment 1-biliary tract stent
Starting material are a kind of hyperelastic NiTi wire rod, diameter 1.5mm.The content of Ti and Ni is respectively 50-50.8at% (at%=accounts for the percentage ratio of total atom number in the alloy) and 49.1at% in the alloy.Handle the sample of described wire rod under 500 ℃ temperature, the time is 1.5 hours, and temperature interval Af-As is determined, the result is 15 ℃.
Then, described wire rod is carried out the thermal treatment first time at 550 ℃, 2 hours time, afterwards, carry out once the electricity irritation of heat-machinery and handle, wherein current density is 900A/cm 2, strain rate is 0.3 second -1Repeat described TMT and handle three times, under 500 ℃, carry out the secondary intermediate heat treatment therebetween, each 1 hour, the thickness of final band was reduced to 0.25mm.
Afterwards, described band is twined and is strapped on the axle that diameter is 8mm, place a vacuum oven and be heated to 500 ℃ to reach 0.6 hour, then, 650 ℃ of solution treatment 30 minutes.Subsequently, 400 ℃ of ageing treatment 1 hour.
The stent that the spiral type that is obtained is batched has 40 ℃ As and 43 ℃ Af.
Then, under 25 ℃ temperature, be to twine on the axle of 3mm described stent, and be heated to and carry out recovery of shape more than 43 ℃ at a diameter.As a result, just obtained to have the stent of round trip SME, the diameter of the austenite shape that it is remembered is 8mm, and when being cooled to below 25 ℃, stent is contracted to the martensitic shape of being remembered, and its diameter is 7.3mm.
For original position is in vivo installed described stent, need it is wrapped on the conduit, embed desired position in the bile duct then.Then, by temperature is risen to 43 ℃ with on activate described stent.For stent is taken away, must be chilled to below 25 ℃, after it shrinks, just stent can be taken out.
Embodiment 2-oesophagus stent
Adopt the TiNi wire rod identical to prepare stent with embodiment 1, described wire rod is carried out the thermal treatment first time, afterwards, carry out TMT again and handle, detailed process is described similar to embodiment 1, and difference is that the final thickness of the wire rod that obtained is 0.28mm.
Then, be to twine and fettered on the axle of 70mm obtaining wire rod at diameter, afterwards, be heated to 500 ℃ and reach 1 hour, carry out solution treatment at 650 ℃ then, the time is 20 minutes.Again described band is wrapped on the axle that diameter is 16mm and is also fettered, carry out memorize at 520 ℃ and handled 30 minutes, then, 400 ℃ of ageing treatment 2 hours, the stent that is obtained after this process has following parameter: As=42 ℃, Af=45 ℃; Martensite transformation temperature is 27 ℃, and stent is expanded during cooling, the 18mm the when 16mm of diameter during by austenitic state swells to martensitic state.
In order to implant, stent is wrapped on the conduit of diameter 5mm, embed desired position in the esophagus, and by be heated to 45 ℃ with on activate.When described stent cooled off, it was expanded, thereby prevents that stent from falling into stomach.
Embodiment 3-oesophagus stent
Adopt with the similar mode of embodiment 2 to prepare stent, difference is described band is wrapped on the axle that diameter is 5mm, and after thermal treatment, is wrapped in opposite direction on the described axle again.After the thermal treatment, similar with embodiment 2, when cooling, the diameter of described stent swells to 25mm from 16mm.
The shape memory strong component of the orthopedic compression screw of embodiment 4-.
Starting material are the NiTi wire rod (Ni that consists of 50.5at% of alloy and the Ti of 49.5at%) of 1.5mm diameter, described wire rod is carried out the thermal treatment first time, carry out TMT afterwards and handle, with embodiment 1 described similar (but use is warm drawing rather than warm-rolling system).
Then, under 500 ℃ temperature,, afterwards, carried out solution treatment 20 minutes at 650 ℃ to the described wire rod heat treated that is in straight restrained condition 0.5 hour.Then, unclamp described wire rod and, it is carried out the memorize processing at 520 ℃, time is 30 minutes, afterwards, and 450 ℃ of ageing treatment 1 hour, described wire rod is being elongated to 21mm from 20mm, just obtaining shape memory effect, wherein, As=39 ℃, Af=41 ℃, after being cooled to the temperature that is no more than 25 ℃, by thermal treatment (not having training process) double process shape-memory effect just appears only, and through (stretching-heating) behind the training process, double process shape-memory effect can increase.
The medical nail of embodiment 5-shape memory
Starting material and processing are all similar to Example 4, the final diameter that is obtained (by warm drawing) 0.25mm.Described wire rod is fettered into necessary shape, and after TMT handles, under 520 ℃, heat treated 0.5 hour, 680 ℃ of following solution treatment 10 minutes, and 450 ℃ of following timeliness 1.5 hours.
After with described nail bending forming, just obtained shape memory effect, wherein As=42 ℃, Af=45 ℃.
Embodiment 6-tooth root implantation piece
Starting material are hyperelastic Buddhist nun Nore (50.8at% Ni) rod too of diameter 10mm, at 550 ℃ described bar are carried out the thermal treatment first time, and the time is 2 hours, afterwards, carries out TMT-and handles 500 ℃ of drawings, and wherein, strain rate is 0.5 second -1Repeat secondary TMT and handle, carry out intermediate heat treatment one time at 500 ℃ therebetween, 1 hour time, the final diameter of described bar is 6.0mm.
Described bar is processed into the shape of tooth root implantation piece, and described implantation piece has 6 pressure portion (leg), so that it is fixed on the jawbone.For different implantation pieces, the length of its described leg is respectively 3,4 and 5mm.Then, at 500 ℃ described value is gone into part and carry out polygonization thermal treatment, 1 hour time, afterwards, the leg of described implantation piece is twisted on axle, subsequently, described implantation piece is heat-treated at 650 ℃, 30 minutes time, and 480 ℃ of timeliness, 1.5 hours time.Then, with the leg of described implantation piece together with beaker flask extruding, (3.0mm the when 5.0mm of diameter during from distortion becomes closed state).When the described implantation piece of heating, at temperature: As=38 ℃ and Af=42 ℃, the leg of implantation piece will launch, thereby jawbone is produced very soft pressure and can obtain activated implantation piece as safe as a house, the leg of implantation piece is carried out that single round-robin stretches and subsequently heat treated can be when the cooling, bring out round trip SME on the closure of described leg, this characteristic is for taking off described implantation piece of great use.
Embodiment 7-has narrow As-Af round trip SM pipe fitting joint at interval.
The NiTi bar that the starting material with among the embodiment 6 of a 10mm are identical adopts with embodiment 6 described same way as to be handled, to obtain the bar of diameter 6mm.Then, described bar is processed into adjustment internal diameter (ID) and is the hollow cylinder of 4.4mm.Afterwards, at 500 ℃ described cylinder is carried out polygonization and handle, 1 hour time, and 680 ℃ of following solution treatment 20 minutes.Cooling then is to swell on the axle of 4.5mm at diameter, and carries out memorize and ageing treatment, is respectively: 530 ℃, and 30 minutes and 430 ℃, 40 minutes.Afterwards, with the cooling of described pipe fitting joint and on axle, swell, so that internal diameter reaches 4.75mm.
After heating (As=15 ℃, Af=18 ℃), described joint connects pipe fitting, and, it has got round trip SME on the direction that ID reduces, therefore, even when cooling, joint also maintains pressure on the pipe fitting that is connected, by contrast, traditional tube stub then is in installation process (swell and heat), produces round trip SME along the direction that swells, and cooling can cause the loosening of pipe fitting joint.

Claims (28)

1. one kind the initial NiTi alloy with original shape handled, the method that has the alloy of net shape with acquisition, under the condition of described net shape, described alloy shows double process shape-memory effect (SME), thereby described alloy has austenite remember condition and Ma Shi remember condition respectively, represents the austenite shape at its austenite remember condition, represent the martensite shape at the martensite remember condition, the step that described method comprises is:
(a), test initial NiTi base alloy, so that the interior tissue of described alloy is estimated by measuring the difference of As and Af, wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) according to the result that obtains in (a), described initial NiTi alloy is carried out the thermal treatment first time, so that the alloy that acquisition has a kind of initial interior tissue condition, under this initial organization condition, dislocation desity at random is basic identical;
(c) described alloy is carried out thermal-mechanical treatment (TMT), be included in the dynamic time effect process, simultaneously described alloy is carried out viscous deformation and heat treated, so that obtain a kind of Polygons subgrain dislocation structure that is distributed with precipitate;
(d) repeating step (c) is until obtaining described net shape; And
(e) described alloy is carried out final thermal treatment and memorize processing, with two remember conditions that obtain to constitute by austenitic state and martensitic state, at described austenitic state, described alloy has austenite form, at described martensitic state, described alloy has the martensite form that deformation extent is higher than described austenite form, and described processing comprises:
(i) described alloy is formed described austenite form; It is carried out polygonization thermal treatment,, carry out solution treatment then, separate out with the dislocation of avoiding not arranging, and it is rearranged, afterwards, carry out ageing treatment so that dislocation is at random arranged; Described alloy is out of shape, so that it represents the adjustment form that a deformation extent is higher than described martensite form, and heats, to obtain described two remember conditions; And
It (ii) is the adjustment form that a kind of deformation extent is higher than described martensite form with described Alloy Forming; And it is heat-treated, carry out polygonization and solution treatment afterwards, and then, randomly carry out ageing treatment; With described Alloy Forming is described austenite form; And, described alloy is carried out memorize thermal treatment and ageing treatment.
2. one kind the initial NiTi alloy with original shape handled, the method that has the alloy of net shape with acquisition, under the condition of described net shape, described alloy shows double process shape-memory effect (SME), thereby described alloy has austenite remember condition and Ma Shi remember condition respectively, represents the austenite shape at its austenite remember condition, represent the martensite shape at the martensite remember condition, the step that described method comprises is:
(a), test initial NiTi base alloy, so that the interior tissue of described alloy is estimated by measuring the difference of As and Af;
(b) according to the result that obtains in (a), described initial NiTi alloy is carried out the thermal treatment first time, so that the alloy that acquisition has a kind of initial interior tissue condition, under this initial organization condition, dislocation desity at random is basic identical;
(c) described alloy is carried out thermal-mechanical treatment (TMT), be included in the dynamic time effect process, simultaneously described alloy is carried out viscous deformation and heat treated, so that obtain a kind of Polygons subgrain dislocation structure that is distributed with precipitate;
(d) described alloy is carried out intermediate heat treatment one time, to finish a circulation that forms the subgrain dislocation structure;
(e) repeating step (c) and (d) is until obtaining described net shape; And
(f) described alloy is carried out final thermal treatment and memorize processing, with two remember conditions that obtain to constitute by austenitic state and martensitic state, at described austenitic state, described alloy has austenite form, at described martensitic state, described alloy has the martensite form that deformation extent is higher than described austenite form, and described processing comprises:
(i) be described austenite form with described Alloy Forming; It is carried out polygonization thermal treatment,, carry out solution treatment then, separate out with the dislocation of avoiding not arranging, and it is rearranged, afterwards, carry out ageing treatment so that dislocation is at random arranged; Described alloy is out of shape, so that it represents the adjustment form that a deformation extent is higher than described martensite form, and heats, to obtain described two remember conditions; And
It (ii) is the adjustment form that a kind of deformation extent is higher than described martensite form with described Alloy Forming; And it is heat-treated, carry out polygonization and solution treatment afterwards, and then, randomly carry out ageing treatment; With described Alloy Forming is described austenite form; And, described alloy is carried out memorize thermal treatment and ageing treatment.
3. according to the method for claim 1, may further comprise the steps:
(a) sample of described initial NiTi alloy is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is less than 7 ℃;
(b) with the temperature of described alloy heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described alloy is carried out (TMT) and handle, comprise with less than 4 seconds -1The described alloy of strain rate viscous deformation, simultaneously, the partial interior that occurs distortion in the described alloy is heated to 250-550 ℃ temperature, the distortion of this step should be lower than 55%;
(d) described alloy is carried out final thermal treatment and memorize processing, with two remember conditions that obtain to constitute by austenitic state and martensitic state, at described austenitic state, described alloy has austenite form, at described martensitic state, described alloy has the martensite form that deformation extent is higher than described austenite form, and described processing comprises:
(i) be described austenite form with described Alloy Forming; It is carried out polygonization thermal treatment,, carry out solution treatment then, separate out with the dislocation of avoiding not arranging, and it is rearranged, afterwards, carry out ageing treatment so that dislocation is at random arranged; Described alloy is out of shape, so that it represents the adjustment form that a deformation extent is higher than described martensite form, and heats, to obtain described two remember conditions; And
It (ii) is the adjustment form that deformation extent is higher than described martensite form with described Alloy Forming; And it is heat-treated, carry out polygonization and solution treatment afterwards, and then, randomly carry out ageing treatment; With described Alloy Forming is described austenite form; And, described alloy is carried out memorize thermal treatment and ageing treatment.
4. according to the method for claim 2, may further comprise the steps:
(a) sample of described initial NiTi alloy is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is less than 7 ℃;
(b) with the temperature of described alloy heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described alloy is carried out (TMT) and handle, comprise with less than 4 seconds -1The described alloy of strain rate viscous deformation, simultaneously, the partial interior that occurs distortion in the described alloy is heated to 250-550 ℃ temperature, the distortion of this step should be lower than 55%;
(d) 500-550 ℃ temperature described alloy is carried out intermediate heat treatment one time, time 0.5-2 hour, then, repeating step (c); And
(e) described alloy is carried out final thermal treatment and memorize processing, with two remember conditions that obtain to constitute by austenitic state and martensitic state, at described austenitic state, described alloy has austenite form, at described martensitic state, described alloy has the martensite form that deformation extent is higher than described austenite form, and described processing comprises:
(i) be described austenite form with described Alloy Forming; It is carried out polygonization thermal treatment,, carry out solution treatment then, separate out with the dislocation of avoiding not arranging, and it is rearranged, afterwards, carry out ageing treatment so that dislocation is at random arranged; Described alloy is out of shape, so that it represents the adjustment form that a deformation extent is higher than described martensite form, and heats, to obtain described two remember conditions; And
It (ii) is the adjustment form that deformation extent is higher than described martensite form with described Alloy Forming; And it is heat-treated, carry out polygonization and solution treatment afterwards, and then, randomly carry out ageing treatment; With described Alloy Forming is described austenite form; And, described alloy is carried out memorize thermal treatment and ageing treatment.
5. according to the method for claim 1, may further comprise the steps:
(a) sample of described initial NiTi alloy is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is greater than 7 ℃;
(b) with the temperature of described alloy heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described alloy is carried out (TMT) and handle, comprise with less than 4 seconds -1The described alloy of strain rate viscous deformation, simultaneously, the partial interior that occurs distortion in the described alloy is heated to 250-550 ℃ temperature, the distortion of this step should be lower than 55%;
(d) described alloy is carried out final thermal treatment and memorize processing, with two remember conditions that obtain to constitute by austenitic state and martensitic state, at described austenitic state, described alloy has austenite form, at described martensitic state, described alloy has the martensite form that deformation extent is higher than described austenite form, and described processing comprises:
(i) be described austenite form with described Alloy Forming; It is carried out polygonization thermal treatment,, carry out solution treatment then, separate out with the dislocation of avoiding not arranging, and it is rearranged, afterwards, carry out ageing treatment so that dislocation is at random arranged; Described alloy is out of shape, so that it represents the adjustment form that a deformation extent is higher than described martensite form, and heats, to obtain described two remember conditions; And
It (ii) is the adjustment form that deformation extent is higher than described martensite form with described Alloy Forming; And it is heat-treated, carry out polygonization and solution treatment afterwards, and then, randomly carry out ageing treatment; With described Alloy Forming is described austenite form; And, described alloy is carried out memorize thermal treatment and ageing treatment.
6. according to the method for claim 2, may further comprise the steps:
(a) sample of described initial NiTi alloy is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is greater than 7 ℃;
(b) with the temperature of described alloy heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described alloy is carried out (TMT) and handle, comprise with less than 4 seconds -1The described alloy of strain rate viscous deformation, simultaneously, the partial interior that occurs distortion in the described alloy is heated to 250-550 ℃ temperature, the distortion of this step should be lower than 55%;
(d) 500-550 ℃ temperature described alloy is carried out intermediate heat treatment one time, time 0.5-2 hour, then, repeating step (c); And
(e) described alloy is carried out final thermal treatment and memorize processing, with two remember conditions that obtain to constitute by austenitic state and martensitic state, at described austenitic state, described alloy has austenite form, at described martensitic state, described alloy has the martensite form that deformation extent is higher than described austenite form, and described processing comprises:
(i) be described austenite form with described Alloy Forming; It is carried out polygonization thermal treatment,, carry out solution treatment then, separate out with the dislocation of avoiding not arranging, and it is rearranged, afterwards, carry out ageing treatment so that dislocation is at random arranged; Described alloy is out of shape, so that it represents the adjustment form that a deformation extent is higher than described martensite form, and heats, to obtain described two remember conditions; And
It (ii) is the adjustment form that deformation extent is higher than described martensite form with described Alloy Forming; And it is heat-treated, carry out polygonization and solution treatment afterwards, and then, randomly carry out ageing treatment; With described Alloy Forming is described austenite form; And, described alloy is carried out memorize thermal treatment and ageing treatment.
7. according to each method among the claim 3-6, the distortion in the wherein said step (C) is lower than 40%.
8. according to each method among the claim 1-7, wherein said final thermal treatment and memorize are handled and are comprised:
(i) be described austenite form with described Alloy Forming;
(ii), described alloy is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, then, at 600-800 ℃ of solution treatment 2-50 minute, afterwards, and at 350-500 ℃, ageing treatment 0.15-2.5 hour, and
(iii) be out of shape described alloy to represent a kind of adjustment form, described distortion should be lower than 15%, and the relational expression below described temperature T satisfies is carried out in described distortion under temperature T
T＜Ms+30℃
Wherein Ms is a Ms (martensite start) point, then described alloy is heated to the temperature of the austenitic transformation end of a period that is equal to or higher than described alloy.
9. method according to Claim 8, wherein, for be presented on step in (iii) the adjustment form and distortion that described alloy is carried out is lower than 7%.
10. according to each method among the claim 1-7, wherein said final thermal treatment and memorize are handled and are comprised:
(i) with described Alloy Forming be described adjustment form;
(ii), described alloy was heat-treated 0.5-2 hour, then, this alloy is carried out polygonization processing and solution treatment 2-50 minute, afterwards,, described alloy was carried out ageing treatment 0-2 hour at 350-500 ℃ at 600-800 ℃ at 450-500 ℃;
Be described austenite form (iii) with described Alloy Forming; And
(iv) at 500-600 ℃, described alloy is carried out memorize thermal treatment, the time surpasses 10 minutes, then, at 350-500 ℃ described alloy is carried out ageing treatment, time 0.15-2.5 hour.
11. according to Claim 8 or 10 method, comprise following additional step:
(g) temperature of austenitic transformation adjust to take place, method therefor be following the two one of:
-under 350-500 ℃ temperature, carry out ageing treatment, to improve the temperature that austenitic transformation takes place, perhaps
-under 510-800 ℃ temperature, carry out solution treatment, to reduce the temperature that austenitic transformation takes place.
12. according to each method among the claim 1-11, wherein said TMT comprises that current density is 500-2000A/cm 2Electricity irritation.
13. method of making medical stent by the NiTi alloy, described alloy is the wire rod with first kind of diameter, the form of described stent or for having the wire rod of second kind of diameter, it perhaps is a kind of band, described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition, it represents the austenite shape when described austenite remember condition, represent the martensite shape when described martensite remember condition, the step that described method comprises is:
(a) sample of described NiTi wire rod is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is less than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The described wire rod of strain rate warm-rolling system, simultaneously, it is 500-2000A/cm that the part that distortion is appearred in described wire rod adopts current density 2Electricity irritation carry out inside heating, the distortion in this step is lower than 55%;
(d) described wire rod is carried out final thermal treatment and memorize processing, it comprises:
(i) wire rod or the band that is obtained in the step (c) is wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(ii), described wire rod is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, then,, carry out solution treatment at 600-800 ℃, time 2-50 minute, afterwards,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) have on a kind of axle of adjusting diameter by described wire rod is wrapped in, come it is out of shape, described distortion should be lower than 7%, and carries out under temperature T, and described temperature T satisfies following relational expression
T＜Ms+30℃
Wherein, Ms is a Ms (martensite start) point, then, described wire rod or band is heated to the temperature that is equal to or higher than the austenitic transformation end of a period,
So far, just obtained a kind of stent, described stent has the diameter that is represented in above-mentioned (i) under its austenitic state, is mid-diameter between between described adjustment diameter and austenite diameter at the diameter under its martensitic state.
14. method of making medical stent by the NiTi alloy, described alloy is the wire rod with first kind of diameter, the form of described stent or for having the wire rod of second kind of diameter, it perhaps is a kind of band, described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition, it represents the austenite shape when described austenite remember condition, represent the martensite shape when described martensite remember condition, the step that described method comprises is:
(a) sample of described NiTi wire rod is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is less than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The described wire rod of strain rate warm-rolling system, simultaneously, it is 500-2000A/cm that the part that distortion is appearred in described wire rod adopts current density 2Electricity irritation carry out inside heating, the distortion in this step is lower than 55%;
(d) under 500-550 ℃ temperature, described wire rod is carried out intermediate heat treatment, time 0.5-2 hour, afterwards, repeating step (c); And
(e) described wire rod is carried out final thermal treatment and memorize processing, it comprises:
(i) wire rod or the band that is obtained in the step (c) is wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(ii), described wire rod is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, then,, carry out solution treatment at 600-800 ℃, time 2-50 minute, afterwards,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) have on a kind of axle of adjusting diameter by described wire rod is wrapped in, come it is out of shape, described distortion should be lower than 7%, and carries out under temperature T, and described temperature T satisfies following relational expression
T＜Ms+30℃
Wherein, Ms is a Ms (martensite start) point, then, described wire rod or band is heated to the temperature that is equal to or higher than the austenitic transformation end of a period,
So far, just obtained a kind of stent, described stent has the diameter that is represented in above-mentioned (i) under its austenitic state, is mid-diameter between between described adjustment diameter and austenite diameter at the diameter under its martensitic state.
15. method of making medical stent by the NiTi alloy, described alloy is the wire rod with first kind of diameter, the form of described stent or for having the wire rod of second kind of diameter, it perhaps is a kind of band, described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition, it represents the austenite shape when described austenite remember condition, represent the martensite shape when described martensite remember condition, the step that described method comprises is:
(a) sample of described NiTi wire rod is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is greater than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The described wire rod of strain rate warm-rolling system, simultaneously, it is 500-2000A/cm that the part that distortion is appearred in described wire rod adopts current density 2Electricity irritation carry out inside heating, the distortion in this step is lower than 55%;
(d) described wire rod is carried out final thermal treatment and memorize processing, it comprises:
(i) wire rod or the band that is obtained in the step (c) is wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(ii), described wire rod is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, then,, carry out solution treatment at 600-800 ℃, time 2-50 minute, afterwards,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) have on a kind of axle of adjusting diameter by described wire rod is wrapped in, come it is out of shape, described distortion should be lower than 7%, and carries out under temperature T, and described temperature T satisfies following relational expression
T＜Ms+30℃
Wherein, Ms is a Ms (martensite start) point, then, described wire rod or band is heated to the temperature that is equal to or higher than the austenitic transformation end of a period,
So far, just obtained a kind of stent, described stent has the diameter that is represented in above-mentioned (i) under its austenitic state, is mid-diameter between between described adjustment diameter and austenite diameter at the diameter under its martensitic state.
16. method of making medical stent by the NiTi alloy, described alloy is the wire rod with first kind of diameter, the form of described stent or for having the wire rod of second kind of diameter, it perhaps is a kind of band, described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition, it represents the austenite shape when described austenite remember condition, represent the martensite shape when described martensite remember condition, the step that described method comprises is:
(a) sample of described NiTi wire rod is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, thus the difference of Af-As that makes described sample is greater than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The described wire rod of strain rate warm-rolling system, simultaneously, it is 500-2000A/cm that the part that distortion is appearred in described wire rod adopts current density 2Electricity irritation carry out inside heating, the distortion in this step is lower than 55%;
(d) under 500-550 ℃ temperature, described wire rod is carried out intermediate heat treatment, time 0.5-2 hour, afterwards, repeating step (c); And
(e) described wire rod is carried out final thermal treatment and memorize processing, it comprises:
(i) wire rod or the band that is obtained in the step (c) is wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(ii), described wire rod is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, then,, carry out solution treatment at 600-800 ℃, time 2-50 minute, afterwards,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) have on a kind of axle of adjusting diameter by described wire rod is wrapped in, come it is out of shape, described distortion should be lower than 7%, and carries out under temperature T, and described temperature T satisfies following relational expression
T＜Ms+30℃
Wherein, Ms is a Ms (martensite start) point, then, described wire rod or band is heated to the temperature that is equal to or higher than the austenitic transformation end of a period,
So far, just obtained a kind of stent, described stent has the diameter that is represented in above-mentioned (i) under its austenitic state, is mid-diameter between between described adjustment diameter and austenite diameter at the diameter under its martensitic state.
17. make the method for medical stent by NiTi wire rod with first kind of diameter; described stent or have diameter be second kind of diameter wire rod form or be a kind of form of band; described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition; wherein; under its austenite remember condition, represent the austenite shape; under the martensite remember condition; represent the martensite shape, the step that described method comprises is:
(a) with the Buddhist nun too the sample of Nore wire rod be heated to 450-550 ℃ temperature, time 0.5-2.5 hour so that the difference of the Af-As of described sample is less than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The described wire rod of strain rate warm-rolling system, adopt electrostimulation to carry out inside to the part that deforms in the described wire rod simultaneously and heat, the current density of electrostimulation is 500-2000A/cm 2, the distortion in this step is lower than 55%;
(d) described wire rod is carried out final thermal treatment and memorize processing, comprising:
(i) will be wrapped on the axle with an adjustment diameter by wire rod or the band that step (c) obtained, the diameter that described adjustment diameter will represent when being in austenitic state with described stent is different,
(ii), described wire rod is heat-treated at 450-500 ℃, time 0.5-2 hour, afterwards,, carry out polygonization and solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0-2 hour,
(iii) described wire rod or band are wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(iv) at 500-600 ℃, described alloy is carried out memorize thermal treatment, the time surpasses 10 minutes, then, at 350-500 ℃, carries out ageing treatment, time 0.15-2.15 hour;
So far, just obtained a kind of stent, it austenitic state have step (iii) described in the diameter of wire rod after being formed, at its martensitic state, the diameter that described stent has is between described adjustment diameter be in mid-diameter between the stent diameter of austenitic state.
18. make the method for medical stent by NiTi wire rod with first kind of diameter; described stent or have diameter be second kind of diameter wire rod form or be a kind of form of band; described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition; wherein; under its austenite remember condition, represent the austenite shape; under the martensite remember condition; represent the martensite shape, the step that described method comprises is:
(a) with the Buddhist nun too the sample of Nore wire rod be heated to 450-550 ℃ temperature, time 0.5-2.5 hour so that the difference of the Af-As of described sample is less than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The described wire rod of strain rate warm-rolling system, adopt electrostimulation to carry out inside to the part that deforms in the described wire rod simultaneously and heat, the current density of electrostimulation is 500-2000A/cm 2, the distortion in this step is lower than 55%;
(d) under 500-550 ℃ temperature, described wire rod is carried out intermediate heat treatment one time, time 0-2 hour, afterwards, repeating step (c); And
(e) described wire rod is carried out final thermal treatment and memorize processing, comprising:
(i) will be wrapped on the axle with an adjustment diameter by wire rod or the band that step (c) obtained, the diameter that described adjustment diameter will represent when being in austenitic state with described stent is different,
(ii), described wire rod is heat-treated at 450-500 ℃, time 0.5-2 hour, afterwards,, carry out polygonization and solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) described wire rod or band are wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(iv) at 500-600 ℃, described alloy is carried out memorize thermal treatment, the time surpasses 10 minutes, then, at 350-500 ℃, carries out ageing treatment, time 0.15-2.15 hour;
So far, just obtained a kind of stent, it has diameter after wire rod is formed described in above-mentioned (i) at austenitic state, at its martensitic state, the diameter that described stent has is between described adjustment diameter be in mid-diameter between the stent diameter of austenitic state.
19. make the method for medical stent by NiTi wire rod with first kind of diameter; described stent or have diameter be second kind of diameter wire rod form or be a kind of form of band; described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition; wherein; under its austenite remember condition, represent the austenite shape; under the martensite remember condition; represent the martensite shape, the step that described method comprises is:
(a) with the Buddhist nun too the sample of Nore wire rod be heated to 450-550 ℃ temperature, time 0.5-2.5 hour so that the difference of the Af-As of described sample is greater than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The described wire rod of strain rate warm-rolling system, adopt electrostimulation to carry out inside to the part that deforms in the described wire rod simultaneously and heat, the current density of electrostimulation is 500-2000A/cm 2, the distortion in this step is lower than 55%;
(d) described wire rod is carried out final thermal treatment and memorize processing, comprising:
(i) will be wrapped on the axle with an adjustment diameter by wire rod or the band that step (c) obtained, the diameter that described adjustment diameter will represent when being in austenitic state with described stent is different,
(ii), described wire rod is heat-treated at 450-500 ℃, time 0.5-2 hour, afterwards,, carry out polygonization and solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0-2 hour,
(iii) described wire rod or band are wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(iv) at 500-600 ℃, described alloy is carried out memorize thermal treatment, the time surpasses 10 minutes, then, at 350-500 ℃, carries out ageing treatment, time 0.15-2.15 hour;
So far, just obtained a kind of stent, it austenitic state have step (iii) described in the diameter of wire rod after being formed, at its martensitic state, the diameter that described stent has is between described adjustment diameter be in mid-diameter between the stent diameter of austenitic state.
20. make the method for medical stent by NiTi wire rod with first kind of diameter; described stent or have diameter be second kind of diameter wire rod form or be a kind of form of band; described stent shows the double process shape-memory effect (SME) with austenite remember condition and martensite remember condition; wherein; under its austenite remember condition, represent the austenite shape; under the martensite remember condition; represent the martensite shape, the step that described method comprises is:
(a) with the Buddhist nun too the sample of Nore wire rod be heated to 450-550 ℃ temperature, time 0.5-2.5 hour so that the difference of the Af-As of described sample is greater than 7 ℃; Wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described wire rod heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described wire rod is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The described wire rod of strain rate warm-rolling system, adopt electrostimulation to carry out inside to the part that deforms in the described wire rod simultaneously and heat, the current density of electrostimulation is 500-2000A/cm 2, the distortion in this step is lower than 55%;
(d) under 500-550 ℃ temperature, described wire rod is carried out intermediate heat treatment one time, time 0-2 hour, afterwards, repeating step (c); And
(e) described wire rod is carried out final thermal treatment and memorize processing, comprising:
(i) will be wrapped on the axle with an adjustment diameter by wire rod or the band that step (c) obtained, the diameter that described adjustment diameter will represent when being in austenitic state with described stent is different,
(ii), described wire rod is heat-treated at 450-500 ℃, time 0.5-2 hour, afterwards,, carry out polygonization and solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0-2 hour,
(iii) described wire rod or band are wrapped on the axle, described axle has the diameter that will represent when described stent is in austenitic state,
(iv) at 500-600 ℃, described alloy is carried out memorize thermal treatment, the time surpasses 10 minutes, then, at 350-500 ℃, carries out ageing treatment, time 0.15-2.15 hour;
So far, just obtained a kind of stent, it austenitic state have step (iii) described in the diameter of wire rod after being formed, at its martensitic state, the diameter that described stent has is between described adjustment diameter be in mid-diameter between the stent diameter of austenitic state.
21. method of making the tooth root implantation piece by the NiTi alloy, this implantation piece shows a kind of double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, it represents the austenite shape at described austenite remember condition, represent the martensite shape at described martensite remember condition, said method comprising the steps of:
(a) sample of NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is less than 7 ℃, wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, strain total in this step is lower than 55%;
(d) described bar is assembled processing, to obtain the shape of described implantation piece;
(e) described implantation piece is carried out final thermal treatment and memorize processing, comprising:
(i) the swell pressure portion of implantation piece so that its have described implantation piece when being in austenitic state with the diameter of showing,
(ii), described implantation piece is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) the pressure portion of described implantation piece is out of shape with strain less than 7%, so that it has a kind of adjustment diameter, and, distortion is carried out under temperature T＜Ms+30 ℃, wherein, Ms is the beginning temperature of martensitic transformation, afterwards, described implantation piece is heated to the finishing temperature that is equal to or higher than austenitic transformation;
So far, just obtained a kind of implantation piece, at its austenitic state, described implantation piece has the diameter of being showed in above-mentioned (i), at its martensitic state, the diameter that described implantation piece has is the mid-diameter between between described adjustment diameter and described austenite diameter.
22. method of making the tooth root implantation piece by the NiTi alloy, this implantation piece shows a kind of double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, it represents the austenite shape at described austenite remember condition, represent the martensite shape at described martensite remember condition, said method comprising the steps of:
(a) sample of NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is less than 7 ℃, wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, strain total in this step is lower than 55%;
(d) at 500-550 ℃, described bar is carried out intermediate heat treatment, time 0.5-2 hour, afterwards, repeating step (c);
(e) described bar is assembled processing, to obtain the shape of described implantation piece;
(f) described implantation piece is carried out final thermal treatment and memorize processing, comprising:
(i) the swell pressure portion of implantation piece so that its have described implantation piece when being in austenitic state with the diameter of showing,
(ii), described implantation piece is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) the pressure portion of described implantation piece is out of shape with strain less than 7%, so that it has a kind of adjustment diameter, and, distortion is carried out under temperature T＜Ms+30 ℃, wherein, Ms is the beginning temperature of martensitic transformation, afterwards, described implantation piece is heated to the finishing temperature that is equal to or higher than austenitic transformation;
So far, just obtained a kind of implantation piece, at its austenitic state, described implantation piece has the diameter of being showed in above-mentioned (i), at its martensitic state, the diameter that described implantation piece has is the mid-diameter between between described adjustment diameter and described austenite diameter.
23. method of making the tooth root implantation piece by the NiTi alloy, this implantation piece shows a kind of double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, it represents the austenite shape at described austenite remember condition, represent the martensite shape at described martensite remember condition, said method comprising the steps of:
(a) sample of NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is greater than 7 ℃, wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, strain total in this step is lower than 55%;
(d) described bar is assembled processing, to obtain the shape of described implantation piece;
(e) described implantation piece is carried out final thermal treatment and memorize processing, comprising:
(i) the swell pressure portion of implantation piece so that its have described implantation piece when being in austenitic state with the diameter of showing,
(ii), described implantation piece is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) the pressure portion of described implantation piece is out of shape with strain less than 7%, so that it has a kind of adjustment diameter, and, distortion is carried out under temperature T＜Ms+30 ℃, wherein, Ms is the beginning temperature of martensitic transformation, afterwards, described implantation piece is heated to the finishing temperature that is equal to or higher than austenitic transformation;
So far, just obtained a kind of implantation piece, at its austenitic state, described implantation piece has the diameter of being showed in above-mentioned (i), at its martensitic state, the diameter that described implantation piece has is the mid-diameter between between described adjustment diameter and described austenite diameter.
24. method of making the tooth root implantation piece by the NiTi alloy, this implantation piece shows a kind of double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, it represents the austenite shape at described austenite remember condition, represent the martensite shape at described martensite remember condition, said method comprising the steps of:
(a) sample of NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is greater than 7 ℃, wherein, As is an austenitic transformation, and promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise with less than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, strain total in this step is lower than 55%;
(d) at 500-550 ℃, described bar is carried out intermediate heat treatment, time 0.5-2 hour, afterwards, repeating step (c);
(e) described bar is assembled processing, to obtain the shape of described implantation piece;
(f) described implantation piece is carried out final thermal treatment and memorize processing, comprising:
(i) the swell pressure portion of implantation piece so that its have described implantation piece when being in austenitic state with the diameter of showing,
(ii), described implantation piece is carried out polygonization thermal treatment at 450-550 ℃, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0.15-2.5 hour,
(iii) the pressure portion of described implantation piece is out of shape with strain less than 7%, so that it has a kind of adjustment diameter, and, distortion is carried out under temperature T＜Ms+30 ℃, wherein, Ms is the beginning temperature of martensitic transformation, afterwards, described implantation piece is heated to the finishing temperature that is equal to or higher than austenitic transformation;
So far, just obtained a kind of implantation piece, at its austenitic state, described implantation piece has the diameter of being showed in above-mentioned (i), at its martensitic state, the diameter that described implantation piece has is the mid-diameter between between described adjustment diameter and described austenite diameter.
25. method of making pipe fitting joint by the NiTi alloy, described pipe fitting joint shows the double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, represent austenitic shape at its austenite remember condition, represent the martensite shape at described martensite remember condition, described method comprises the following steps:
(a) sample of described NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is less than 7 ℃, wherein As was an austenitic transformation, promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, the overall strain in this step is lower than 55%;
(d) described bar is carried out machining, to obtain to be shaped as joint with hollow cylinder of adjusting internal diameter;
(e) described cylinder is carried out final thermal treatment and memorize processing, comprising:
(i) at 450-550 ℃, described cylinder is carried out polygonization thermal treatment, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0-2.5 hour,
The described cylinder that (ii) swells so that its have described joint when being in austenitic state with the diameter of showing,
(iii) at 500-600 ℃, described cylinder is carried out memorize handle, the time surpasses 10 minutes, afterwards, at 350-500 ℃, carries out ageing treatment, and time 0.15-2.5 hour,
So far, just obtained a kind of joint that has austenitic state and martensitic state respectively, at described austenitic state, described joint has its diameter after step is formed in (ii), at described martensitic state, the diameter that described joint has is the mid-diameter of the diameter when described adjustment internal diameter and joint are in austenitic state.
26. method of making pipe fitting joint by the NiTi alloy, described pipe fitting joint shows the double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, represent austenitic shape at its austenite remember condition, represent the martensite shape at described martensite remember condition, described method comprises the following steps:
(a) sample of described NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is less than 7 ℃, wherein As was an austenitic transformation, promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 450-500 ℃, time 0.5-1.0 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, the overall strain in this step is lower than 55%;
(d) under 500-550 ℃ temperature, described bar is carried out intermediate heat treatment, time 0.5-2 hour, afterwards, repeating step (c); And
(e) described bar is carried out machining, to obtain to be shaped as joint with hollow cylinder of adjusting internal diameter;
(f) described cylinder is carried out final thermal treatment and memorize processing, comprising:
(i) at 450-550 ℃, described cylinder is carried out polygonization thermal treatment, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0-2.5 hour,
The described cylinder that (ii) swells so that its have described joint when being in austenitic state with the diameter of showing,
(iii) at 500-600 ℃, described cylinder is carried out memorize handle, the time surpasses 10 minutes, afterwards, at 350-500 ℃, carries out ageing treatment, and time 0.15-2.5 hour,
So far, just obtained a kind of joint that has austenitic state and martensitic state respectively, at described austenitic state, described joint has its diameter after step is formed in (ii), at described martensitic state, the diameter that described joint has is the mid-diameter of the diameter when described adjustment internal diameter and joint are in austenitic state.
27. method of making pipe fitting joint by the NiTi alloy, described pipe fitting joint shows the double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, represent austenitic shape at its austenite remember condition, represent the martensite shape at described martensite remember condition, described method comprises the following steps:
(a) sample of described NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is greater than 7 ℃, wherein As was an austenitic transformation, promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, the overall strain in this step is lower than 55%;
(d) described bar is carried out machining, to obtain to be shaped as joint with hollow cylinder of adjusting internal diameter;
(e) described cylinder is carried out final thermal treatment and memorize processing, comprising:
(i) at 450-550 ℃, described cylinder is carried out polygonization thermal treatment, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0-2.5 hour,
The described cylinder that (ii) swells so that its have described joint when being in austenitic state with the diameter of showing,
(iii) at 500-600 ℃, described cylinder is carried out memorize handle, the time surpasses 10 minutes, afterwards, at 350-500 ℃, carries out ageing treatment, and time 0.15-2.5 hour,
So far, just obtained a kind of joint that has austenitic state and martensitic state respectively, at described austenitic state, described joint has its diameter after step is formed in (ii), at described martensitic state, the diameter that described joint has is the mid-diameter of the diameter when described adjustment internal diameter and joint are in austenitic state.
28. method of making pipe fitting joint by the NiTi alloy, described pipe fitting joint shows the double process shape-memory effect that has austenite remember condition and martensite remember condition respectively, represent austenitic shape at its austenite remember condition, represent the martensite shape at described martensite remember condition, described method comprises the following steps:
(a) sample of described NiTi bar is heated to 450-550 ℃ temperature, time 0.5-2.5 hour, so that the difference of described its Af-As is greater than 7 ℃, wherein As was an austenitic transformation, promptly by the beginning temperature of martensitic state to the austenitic state transformation, Af is the finishing temperature of austenitic transformation;
(b) with the temperature of described bar heat treated to 510-550 ℃, time 1.0-2.5 hour;
(c) described bar is carried out thermal-mechanical treatment, comprise to be lower than 5 seconds -1The drawing of strain rate temperature, heat simultaneously, the overall strain in this step is lower than 55%;
(d) under 500-550 ℃ temperature, described bar is carried out intermediate heat treatment, time 0.5-2 hour, afterwards, repeating step (c); And
(e) described bar is carried out machining, to obtain to be shaped as joint with hollow cylinder of adjusting internal diameter;
(f) described cylinder is carried out final thermal treatment and memorize processing, comprising:
(i) at 450-550 ℃, described cylinder is carried out polygonization thermal treatment, time 0.5-1.5 hour, afterwards,, carry out solution treatment at 600-800 ℃, time 2-50 minute, then,, carry out ageing treatment at 350-500 ℃, time 0-2.5 hour,
The described cylinder that (ii) swells so that its have described joint when being in austenitic state with the diameter of showing,
(iii) at 500-600 ℃, described cylinder is carried out memorize handle, the time surpasses 10 minutes, afterwards, at 350-500 ℃, carries out ageing treatment, and time 0.15-2.5 hour,
So far, just obtained a kind of joint that has austenitic state and martensitic state respectively, at described austenitic state, described joint has its diameter after step is formed in (ii), at described martensitic state, the diameter that described joint has is the mid-diameter of the diameter when described adjustment internal diameter and joint are in austenitic state.
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CN103310826B (en) * 2012-03-16 2016-12-14 联想(北京)有限公司 Hard disk support bracket
CN107475652B (en) * 2017-08-22 2019-03-05 哈尔滨工程大学 A method of there are sections for R phase in regulation TiNi base memorial alloy
CN111150531A (en) * 2019-12-11 2020-05-15 浙江大学 Rehabilitation orthosis for unstable ankle joint
CN115233122A (en) * 2022-07-27 2022-10-25 天津大学 Training method for NiTi alloy two-way shape memory effect and product thereof

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