CN109182863A - Method for extruding magnesium alloy at high speed - Google Patents
Method for extruding magnesium alloy at high speed Download PDFInfo
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- CN109182863A CN109182863A CN201811354493.3A CN201811354493A CN109182863A CN 109182863 A CN109182863 A CN 109182863A CN 201811354493 A CN201811354493 A CN 201811354493A CN 109182863 A CN109182863 A CN 109182863A
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- 229910000861 Mg alloy Inorganic materials 0.000 title claims abstract description 159
- 238000000034 method Methods 0.000 title claims abstract description 81
- 238000001125 extrusion Methods 0.000 claims abstract description 72
- 238000001953 recrystallisation Methods 0.000 claims abstract description 52
- 238000007906 compression Methods 0.000 claims abstract description 30
- 230000006835 compression Effects 0.000 claims abstract description 29
- 238000012360 testing method Methods 0.000 claims abstract description 14
- 238000012545 processing Methods 0.000 claims abstract description 12
- 238000004088 simulation Methods 0.000 claims abstract description 12
- 238000000137 annealing Methods 0.000 claims abstract description 7
- 238000012216 screening Methods 0.000 claims abstract description 3
- 239000000956 alloy Substances 0.000 claims description 17
- 229910045601 alloy Inorganic materials 0.000 claims description 15
- 238000005275 alloying Methods 0.000 claims description 11
- 239000011777 magnesium Substances 0.000 claims description 10
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 9
- 229910052749 magnesium Inorganic materials 0.000 claims description 9
- 238000009749 continuous casting Methods 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 6
- 239000004615 ingredient Substances 0.000 claims description 5
- 238000004364 calculation method Methods 0.000 claims description 4
- 238000004891 communication Methods 0.000 claims description 3
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 2
- 239000004753 textile Substances 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 20
- 230000007246 mechanism Effects 0.000 abstract description 10
- 238000005266 casting Methods 0.000 abstract description 5
- 238000001192 hot extrusion Methods 0.000 abstract description 4
- 238000011161 development Methods 0.000 abstract description 2
- 239000013078 crystal Substances 0.000 description 8
- 238000012827 research and development Methods 0.000 description 7
- 230000006911 nucleation Effects 0.000 description 6
- 238000010899 nucleation Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 238000011160 research Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 229910000765 intermetallic Inorganic materials 0.000 description 4
- 239000002893 slag Substances 0.000 description 4
- 230000001419 dependent effect Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000004224 protection Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000003870 refractory metal Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000952 Be alloy Inorganic materials 0.000 description 1
- 201000004569 Blindness Diseases 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910020054 Mg3Bi2 Inorganic materials 0.000 description 1
- 229910000914 Mn alloy Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 229910000905 alloy phase Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000012669 compression test Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 235000012438 extruded product Nutrition 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000010309 melting process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C23/00—Alloys based on magnesium
- C22C23/04—Alloys based on magnesium with zinc or cadmium as the next major constituent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/03—Making non-ferrous alloys by melting using master alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/06—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of magnesium or alloys based thereon
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Extrusion Of Metal (AREA)
Abstract
The invention relates to a method for extruding magnesium alloy at a high speed, belonging to the technical field of hot extrusion processing of magnesium alloy. The method comprises the following steps: 1) designing a rapid extrusion magnesium alloy component range by a microalloying means, casting and homogenizing annealing, 2) researching the thermal deformation behavior of the magnesium alloy annealed in the step 3) under different deformation temperatures and strain rates through a thermal compression simulation test, observing a microstructure, and screening magnesium alloy components capable of performing twin dynamic recrystallization at a low deformation temperature and a high strain rate; 3) calculating the critical strain of twinning dynamic recrystallization of the magnesium alloy according to a thermal compression simulation test, performing fast/high-speed compression upsetting deformation at the stage before the magnesium alloy is extruded to the critical strain, and continuing extrusion deformation after the critical strain is reached. The method establishes a method for establishing the magnesium alloy capable of being extruded rapidly by utilizing a twin dynamic recrystallization mechanism through a microalloying means, and has important guiding significance for the development of the rapid extrusion deformation process of the magnesium alloy.
Description
Technical field
The invention belongs to magnesium alloy hot extrusion processing technique field more particularly to a kind of twin dynamic recrystallization mechanism of utilization
The method for realizing high-speed extrusion magnesium alloy.
Background technique
Magnesium alloy as most light structural material, have high specific strength, high specific stiffness, high damping vibration attenuation, thermal conductivity and
The advantages that electromagnetic shielding performance is excellent a, it has also become important research direction of conservation-minded society.Magnesium-alloy tube, stick, profile etc.
Deformed items, it is main to be produced by pressing method, have in fields such as communications and transportation, textile machine, defence and military and aerospaces
Have broad application prospects.
However, the structure cell due to magnesium is close-packed hexagonal structure, theoretical slip system is few, and plastic forming ability is poor, causes to squeeze
The problems such as speed is low and processing cost is high constrains the industrialized development and engineering application of magnesium alloy deformation material.For example, common
AZ80 and ZK60 magnesium alloy extrusion speed there was only 0.5~2.5m/min, the 1/10 of only aluminium alloy extruded speed, and need
It is realized at a high temperature of 400 DEG C or more, extruding difficulty is big, energy consumption is high, increases manufacturing cost.
In high-speed deformation, the slip system of starting can increase magnesium alloy, i.e., equivalent slip resistance increases, and cause to generate
A large amount of deformation heats.When extrusion speed increases, deformation heat steeply rises the temperature at mould outlet, and the extruding temperature rise of generation can make
It is dissolved at the intermetallic compound of low melting point, pinning cannot be played the role of and crystal grain is prevented to grow up, cause squeeze wood tissue thick
Big and mechanical property reduces.Currently, can high-speed extrusion wrought magnesium alloy exploitation, mainly from high-speed extrusion process generate temperature
Emersion hair prepares the deformed magnesium alloy material containing compound between refractory metal by alloying, to hinder recrystal grain
The generation of profile fire check is grown up and prevented, realizes high-speed extrusion.It is in situ when hot extrusion by taking Mg-Bi-Al-Zn-Mn alloy as an example
Generate dystectic Mg3Bi2Phase (823 DEG C of fusing point), it can be achieved that higher deformation temperature (450 DEG C of highest) and be not less than 20m/min
High-speed extrusion.Mg-Al-Mn-Si-Ce-Y-Sr-Sb wrought magnesium alloy passes through a variety of alloying elements and the compound addition of rare earth element
Compound between production refractory metal, makes its extrusion speed maximum up to 15m/min.Patent application 201610975794.2 proposes
Mg-Zn-Sn-Al-Sr-Mn-Ce-Be alloy and patent application 201010152389.3 propose Mg-Al-Mn-Si-Ce-Y-
Although the extrusion process of fair speed can be achieved in two kinds of magnesium alloys of Sr-Sb, this kind of magnesium alloy addition element type is more, causes
Its preparation process is complicated, at high cost.
Earlier application 201710028472.1 of the invention discloses a kind of heat processing technique optimization side of wrought magnesium alloy
Method, it is to develop rule by calculating control dynamic recrystallization according to thermodynamics, the dynamic characteristic in magnesium alloy thermal deformation process
Rule selects suitable thermal process parameter, so as to improve magnesium alloy plastic forming ability, effectively controls the microstructure evolution of alloy,
Its hot-working productivity and modified product quality are improved, the excellent wrought magnesium alloy of fine microstructures, comprehensive mechanical property is obtained and produces
Product.But this method optimizes the microstructure of magnesium alloy just for the sake of predicting thermal process parameter more accurately
And mechanical property, the ability that magnesium alloy can not be made to have rapid deformation.
Generally speaking, it is current can high-speed extrusion wrought magnesium alloy research on the whole still in the laboratory exploratory stage,
R&D process lacks theoretical guide, and based on test process is instructed with experience, there are biggish contingency for R&D process, cause existing
Can high-speed extrusion deformation magnesium alloy type it is few, formulate the deformation characteristic of deformation technique and magnesium alloy itself and mismatch, and greatly
There is the problems such as complicated component and general comprehensive mechanical property more.Therefore, needing to establish one kind helps that people is instructed to design
The theoretical method of the reasonable magnesium alloy deformed suitable for crushing failure at high speed and deformation technique, at least to solve above-mentioned subproblem.
Summary of the invention
For above-mentioned problems of the prior art, the present invention is intended to provide a kind of method of high-speed extrusion magnesium alloy,
Present invention proposition is started with from deformation mechanism, by microalloying means, utilizes a set of energy of twin dynamic recrystallization Mechanism establishing
It is enough formulate can crushing failure at high speed magnesium alloy guidance method, make research and development precision, the targeted of magnesium alloy crushing failure at high speed technique, significantly
Reduce contingency, blindness existing for R&D process；The magnesium alloy that crushing failure at high speed obtains is carried out under the method for the present invention guidance
Crystal grain is tiny, and comprehensive mechanical property is excellent, illustrates that method of the invention has good feasibility, becomes to magnesium alloy crushing failure at high speed
The exploitation of shape technique has important theoretical direction and realistic meaning.
An object of the present invention is to provide a kind of method of high-speed extrusion magnesium alloy.
The second object of the present invention is to provide the application of the magnesium alloy of the method for above-mentioned high-speed extrusion magnesium alloy and its preparation.
For achieving the above object, specifically, the invention discloses following technical proposals:
Firstly, a kind of method that the present invention discloses high-speed extrusion magnesium alloy, includes the following steps:
(1) crushing failure at high speed magnesium alloy composition range is designed by microalloying means；
(2) by the magnesium alloy cast in step (1) at as-cast magnesium alloy,
(3) by as-cast magnesium alloy in hot Compression Simulation experimental study step (2) in different distortion temperature and strain rate
Under hot deformation behavior, then by observation microscopic structure, screening can occur twin under low deformation temperature and high strain rate
The magnesium alloy ingredient of raw dynamic recrystallization；
(4) according to hot Compression Simulation test obtained in data the magnesium alloy that filters out in step (3) be calculated occur
The critical strain of twin dynamic recrystallization；
(5) fast/high-speed extrusion deformation technique of magnesium alloy is formulated: twin dynamic recrystallization can occur in step (3)
Low deformation temperature and high strain rate be fast/high-speed extrusion processing parameters, before magnesium alloy extrusion to critical strain
Stage carries out fast/high speed compression mushrooming deformation, continues to be squeezed and deformed after reaching critical strain, make magnesium alloy be full of just entirely by
The enclosure space that extrusion cylinder, pressure ram and extrusion die are formed.
In step (1), the microalloying means are to add trace alloying element on the basis of the existing magnesium alloy trade mark
Improve the structure property of alloy, in order to do the preparation of microstructure, aspect of performance for the deformation of the crushing failure at high speed of magnesium alloy；With existing
Some designed based on the magnesium alloy trade mark the advantages of crushing failure at high speed magnesium alloy be research and development cost it is relatively lower, additionally it is possible to meet not
Service demand of the same domain to magnesium alloy.
In step (1), the microalloying means may be with magnesium alloy for basic element, addition microalloy member
Element, to improve the structure property of alloy, the advantage of this design method is to can according to need to design completely new magnesium alloy, is met
New performance requirement.
In step (1), the alloying element includes rare earth element (such as common Y, Ce, Nd, Gd), alkaline earth element (Ca)
Facilitate the as-cast structure that magnesium alloy obtains fine uniform Deng, this kind of alloying element；By taking Y element as an example, Y can reduce magnesium alloy
The solid/liquid interfaces tension of melt, declines nucleating work, and Critical nucleation radius reduces, and forming core is more easier.Y element can also become
The forming core core of Mg matrix can also form the core that the high-melting-point alloy containing Y is mutually used as non-spontaneous forming core in process of setting, resistance
Crystal grain is hindered to be grown up.The ingredient of high-melting-point alloy phase containing Y element, which is reallocated, also results in the solid/liquid interfaces of dendritic growth with segregation
Forward position constitutional supercooling district increases, and then accelerates forming core rate, makes interdendritic away from reduction, achievees the effect that thinning microstructure；But when Y contains
When measuring larger, grain refining effect can weaken.
Further, in step (1), the content of the micro alloying element for addition is no more than 1.0%, but is not
0%；Because addition element carries out alloying in the magnesium alloy, although the structure property of magnesium alloy materials can be improved, with
The increase of addition element content, content, the distributional pattern etc. of intermetallic compound are all unfavorable for being plastically deformed in magnesium alloy, instead
The difficulty that will increase hot extrusion be easy to cause magnesium alloy to open especially for the magnesium alloy for needing to deform under fast/high-speed condition
It splits or extruding force significantly increases.
In step (3), the low deformation temperature refers to deformation temperature at 400 DEG C hereinafter, the high strain rate refers to judgement of speed change
Rate is in 1s-1More than.Lower deformation temperature is conducive to twin generation, and temperature is too high to be unfavorable for twin dynamic recrystallization, and temperature
It is too high, squeeze temperature rise will cause extrusion die outlet it is excessively high, be unfavorable for the structure property of extruded product.High strain rate is also advantageous
In twin, the nucleation point of increase twin dynamic recrystallization；When strain rate is greater than 1s-1When, it is more advantageous at deformation initial stage twin
Generation；The twin sensibility to strain rate is much larger than the sensibility to deformation temperature.It therefore, can by improving deformation velocity
Significantly improve twin tendency.The initial stage of thermal deformation, some magnesium alloys are carried out under lower deformation temperature and high strain rate
Material often needs twin starting with compatible deformation, and with continuing for deformation, it is twin that deformation twins then become nucleation point generation
Dynamic recrystallization.In this way, twin dynamic recrystallization is transformed by the present invention by controlling and utilizing twin dynamic recrystallization behavior
A kind of very effective mode of deformation and energy storage is discharged in magnesium alloy high speed extrusion process, and then is realized the quick of magnesium alloy and squeezed
Pressure, in addition, twin dynamic recrystallization or a kind of important softening and grain refinement mechanism, can not only discharge deformation and energy storage,
Also have a very important role to control material Deformation structure, improvement plastic forming ability and its comprehensive mechanical property.
Preferably, the low deformation temperature refers to: deformation temperature is between 250-350 DEG C；In this temperature range, more favorably
In twin.
It should be noted that the low deformation temperature and high strain rate are an opposite concepts in step (3),
It does not need to be confined in some specific value range, for example, after technical staff fully understands technical thought of the invention,
Suitable low change can be established by conventional repetition test according to ingredient, the expected performance for needing to obtain etc. of magnesium alloy
Shape temperature and high strain rate；The value range of above-mentioned deformation temperature and high strain rate that the present invention provides is used for the purpose of making skill
The illustrative explanation of one kind of technical solution of the present invention can be more clearly understood in art personnel, be not meant to that all magnesium closes
Jin Jun is suitable for above parameter range.
In step (4), the calculation method of the limit stress are as follows: according to hot Compression Simulation test obtained in data creating
True stress-true strain curve (σ-ε curve), according to σ-ε curve, seeks first derivativeθ-ε curve is obtained, ε is asked using θ
Single order local derviation, obtainsWith the relational graph of σ, the minimum value of ordinate (σ) is obtained from the relational graph, then is obtained
Take the corresponding abscissa of the minimum valueValue, as limit stress；Origin, Excel etc. can be used in above-mentioned derivation process
Software realization.
Preferably, in step (2), as-cast magnesium alloy is obtained using water cooling semi-continuous casting method, to obtain fine uniform
As-cast structure.
Preferably, in step (2), homogenizing annealing processing is carried out to as-cast magnesium alloy；Homogenizing annealing processing intent is
Dendritic segregation and component segregation are eliminated, intermetallic compound Dispersed precipitate is made, may advantageously facilitate twin dynamic during high-speed deformation
The forming core of state recrystallization.
Secondly, the present invention discloses the magnesium alloy of the method preparation of above-mentioned high-speed extrusion magnesium alloy.
Finally, the present invention discloses the method for above-mentioned high-speed extrusion magnesium alloy and its magnesium alloy of preparation in communications and transportation, spinning
Application in the fields such as loom tool, defence and military and aerospace.
In step (3) of the present invention, by hot Compression Simulation method may determine that designed alloy can high-speed deformation (i.e.
High strain rate) and lower deformation temperature under twin dynamic recrystallization behavior occurs, and then filter out twin dynamic can occur
The reason of magnesium alloy of recrystallization, selection has the magnesium alloy of this characteristic, is: (1) magnesium alloy equivalent lattice in high-speed deformation
The increase of skid resistance can generate a large amount of deformation heats, and deformation heat steeply rises the temperature at mould outlet, the extruding temperature of generation
The intermetallic compound dissolution that will cause low melting point is risen, pinning cannot be played the role of and crystal grain is prevented to grow up, lead to squeeze wood
Organizational coarseness and mechanical property reduce, and therefore, selection can occur twin under lower deformation temperature as far as possible
Magnesium alloy, fast/high-speed deformation can also be occurred by making magnesium alloy at low temperature using twin dynamic recrystallization, alleviated deformation heat and caused
Low-melting-point metal between compound dissolution.(2) present invention by magnesium alloy in thermal deformation process deformation temperature, judgement of speed change
Rate and dependent variable find the research of dynamic recrystallization volume fraction affecting laws: when within the scope of certain strain rate (such as
0.001-0.01s-1), with the reduction of deformation temperature, dependent variable to be achieved needed for reaching identical dynamic recrystallization volume fraction
Increase, illustrates that lower deformation temperature can postpone the twin dynamic recrystallization of magnesium alloy；On the contrary, in high strain rate deformation condition
Under (such as 1s-1), with the raising of deformation temperature, the dependent variable for reaching identical dynamic recrystallization volume fraction increases instead.It can be with
Find out: lower deformation temperature and high strain rate can induce twin dynamic recrystallization.
In step (5) of the present invention, will be in this specific timing node of the stage before magnesium alloy extrusion to critical strain
The reason of addition " fast/high speed compression mushrooming deformation " this special process is: the present invention is first calculated when initially testing
After the critical strain of twin dynamic recrystallization occurs for magnesium alloy, it is equivalent to and only obtains the twin dynamic recrystallization of magnesium alloy generation
An opportunity, but this to realize magnesium alloy high-speed extrusion deformation do not bring further effect, in order to sufficiently benefit
With this calculated result, the present invention through further research, it has been found that, for the magnesium alloy after different microalloyings, i.e., enabled hair
Raw twin recrystallization, as the difference of deformation temperature and lead to critical strain needed for twin dynamic recrystallization occurs not
Together, low rate of deformation is unfavorable for twin, and generation twin density is low, cannot utilize the twin Plastic Forming energy for improving deformation initial stage
Power is also unfavorable for providing more nucleation mass points for subsequent dynamic recrystallization, is unfavorable for subsequent fast/high-speed deformation；For this purpose,
The present invention selects lower deformation temperature, and the stage before magnesium alloy extrusion to critical strain carries out fast/high ram compression to magnesium alloy
Contracting mushrooming deformation not only can shorten the time that twin dynamic recrystallization occurs for magnesium alloy, and can utilize Large strain
Rate further increases the twin density in ingot casting, increases the nucleation mass point of dynamic recrystallization, has well solved magnesium alloy and has existed
The problem of being brought when carrying out crushing failure at high speed using twin dynamic recrystallization mechanism at a temperature of lower extruding.In magnesium alloy thermal deformation
Cheng Zhong, lower deformation temperature and high strain rate can promote twin formation, and the twin sensibility to strain rate is much
Greater than the sensibility to deformation temperature, therefore, the present invention by the addition of stage before magnesium alloy extrusion to critical strain " it is fast/
This technique of high speed compression mushrooming deformation " improves the twin tendency of magnesium alloy；Further, the present invention utilizes twin to sliding
Facilitation and its contribution to deformation, to improve the plastic deformation ability of magnesium alloy, because in lower deformation temperature and height
The initial stage deformed under strain rate needs twin starting with compatible deformation, because the slip system of magnesium alloy is considerably less, nothing
Method is obtaining high plastic deformation by sliding at the very start, and after twin starting, the twin formed during deformation after unloading is then
The nucleation point of dynamic recrystallization, i.e. generation twin dynamic recrystallization can be become.It therefore, can using twin dynamic recrystallization mechanism
To be effectively improved plastic deformation ability of the magnesium alloy under lower deformation temperature and deformation speed, improves magnesium alloy high speed and squeeze
The ability of deformation.
Compared with prior art, the beneficial effect that the present invention obtains is:
(1) stage of the present invention before magnesium alloy extrusion to critical strain carries out fast/upset change of high speed compression to magnesium alloy
Shape not only can shorten the time that twin dynamic recrystallization occurs for magnesium alloy, and can further increase in ingot casting
Twin density has well solved magnesium alloy and has carried out crushing failure at high speed using twin dynamic recrystallization mechanism at a temperature of lower extruding
When the problem of bringing.
(2) present invention passes through the stage addition " fast/high speed compression mushrooming deformation " before magnesium alloy extrusion to critical strain
This technique improves the twin tendency of magnesium alloy；On this basis, the present invention using the twin facilitation to sliding and its
Contribution to deformation improves the plastic deformation ability of magnesium alloy.
(3) it by microalloying means, can quickly be squeezed using a set of can formulate of twin dynamic recrystallization Mechanism establishing
The guidance method for pressing magnesium alloy, the magnesium alloy crystal grain that progress crushing failure at high speed obtains under the method for the present invention guidance is tiny, mechanical property
It can be excellent, it was demonstrated that method proposed by the present invention has good feasibility.
Detailed description of the invention
The accompanying drawings constituting a part of this application is used to provide further understanding of the present application, and the application's shows
Meaning property embodiment and its explanation are not constituted an undue limitation on the present application for explaining the application.
Fig. 1 is metallographic microscope of the magnesium alloy of 1 heterogeneity of embodiment under different distortion amount.
Fig. 2 is 1 magnesium alloy of embodiment in 300 DEG C of -1s of deformation condition-1Under true stress-true strain curve (σ-ε curve) and
First derivative is asked to the curveObtained θ-ε curve.
Fig. 3 is embodiment 1With the relational graph of σ.
Fig. 4 is the schematic diagram that magnesium alloy high speed compresses the mushrooming deformation stage in embodiment 1.
Fig. 5 is the macro morphology (a) and stretching mechanical property testing figure for the magnesium alloy that embodiment 2 is obtained by high-speed extrusion
(b)。
Specific embodiment
It is noted that following detailed description is all illustrative, it is intended to provide further instruction to the application.Unless another
It indicates, all technical and scientific terms used herein has usual with the application person of an ordinary skill in the technical field
The identical meanings of understanding.
It should be noted that term used herein above is merely to describe specific embodiment, and be not intended to restricted root
According to the illustrative embodiments of the application.As used herein, unless the context clearly indicates otherwise, otherwise singular
Also it is intended to include plural form, additionally, it should be understood that, when in the present specification using term "comprising" and/or " packet
Include " when, indicate existing characteristics, step, operation, device, component and/or their combination.
As background technique is introduced, it is current can the research of high-speed extrusion wrought magnesium alloy explored still in laboratory
Stage, R&D process lack theoretical guide, and based on test process is instructed with experience, R&D process is led there are biggish contingency
Cause it is existing can high-speed extrusion deformation magnesium alloy type it is few, and ask mostly there are complicated component and comprehensive mechanical property are general etc.
Topic.Therefore, the present invention propose it is a kind of using twin dynamic recrystallization mechanism exploitation can crushing failure at high speed magnesium alloy method, below
In conjunction with the drawings and the specific embodiments, the present invention is described further.
In the present invention, term " microalloying " refers to is added suitable microalloying alloy member in the basic ingredient of the alloy
Element, for example, the Mg-2.0Zn-0.3Zr-0.9Y magnesium alloy in the embodiment of the present invention, is on the basis of Mg-2.0Zn-0.3Zr
It joined the Y that mass percent is 0.9% and formed.
In the present invention, term " twin dynamic recrystallization " refers in magnesium alloy thermal deformation process, as intra-die dislocation is close
Degree constantly accumulation generates a large amount of twins, and reciprocation during deformation after unloading between twin makes forming core inside twin that dynamic occur
Recrystallization, i.e., twin dynamic recrystallization.
In the present invention, term " twinning deformation " refers to that twinning deformation is the atom of crystal particular crystal plane (twin plane) along certain side
The result of displacement (referred to as shear) is cooperateed with to (twin direction).
In the present invention, term " rapid deformation " refers to that the rate of the extrusion deformation of magnesium alloy reaches 10-20m/min.
In the present invention, term " high-speed deformation " refers to that the rate of the extrusion deformation of magnesium alloy reaches 20m/min or more.
In the following example, the water cooling semi-continuous casting method refers to: in by preheating resistance furnace, being added by pre-
Hot temperature is higher than 150 DEG C of magnesium ingot, is heated between 350-400 DEG C, keeps the temperature 20 minutes.No. 5 flux protections in magnesium ingot surface, and
Resistance furnace furnace temperature is risen to 880 DEG C, melts magnesium ingot all.After magnesium ingot all fusing, molten surface slag is removed.Whole magnesium
In 720 DEG C of -730 DEG C of removing slags after ingot fusing, No. 5 flux are added in melt liquid level, pure Zn is then added, are stirred 3-5 minutes.
Zinc to be added all after fusing, adds No. 5 flux covering molten surfaces, is warming up to 760 DEG C, removes molten surface slag, be added
Mg-31%Zr intermediate alloy and Mg-30%Y intermediate alloy are stirred melt 3-5 minutes.It is molten that molten surface is removed again
Slag covers appropriate No. 5 flux in molten surface, and stands 20min.After resistance furnace power-off, 710 DEG C are down to furnace temperature, passes through water
Cold semi-continuous casting system is cast into the ingot casting of Ф 92mm.CO is used in entire melting and casting process2(99vol.%) and SF6
(1vol.%) mixed gas is protected.
It should be noted that technological parameter of water cooling semi-continuous casting method etc. can be according to specific different magnesium alloy
It is adjusted, which can decide whether to add according to different magnesium alloys.
Embodiment 1
A kind of method of high-speed extrusion magnesium alloy, includes the following steps:
(1) based on existing Mg-2.0Zn-0.3Zr, alloy is prepared using microalloying means, adds Y element system
Standby Mg-2.0Zn-0.3Zr-0.9Y and Mg-2.0Zn-0.3Zr-5.8Y, is closed both magnesium using water cooling semi-continuous casting method
Gold is prepared into as-cast magnesium alloy, then both alloys are carried out the processing of 420 DEG C × 12h homogenizing annealing；
(2) thermal simulation experiment sample is prepared respectively with two kinds of magnesium alloys after annealing in step (1), specimen size is
φ 10mm × 12mm carries out the heat under different distortion temperature and high strain rate on Gleeble 1500D hot modeling test machine
Simulated experiment.Deformation temperature is selected as 250 DEG C, 300 DEG C, 350 DEG C, 400 DEG C and 450 DEG C, and high strain rate is set as 1s-1, deformation
Amount is respectively set to 0.153,0.611 and 0.916, stops compression after reaching default deflection, carries out to compression sample rapidly
Quenching is as shown in Figure 1 to retain microscopic structure state when high temperature, wherein Fig. 1 (a) is 300 DEG C of deformation temperature, rate of deformation
1s-1, deflection 0.153 (true strain) metallograph, Fig. 1 (b) is 300 DEG C of deformation temperature, rate of deformation 1s-1, deflection is
The metallograph of 0.611 (true strain) can be seen that Mg-2.0Zn-0.3Zr-0.9Y magnesium alloy lower from Fig. 1 (a), (b)
Twin dynamic recrystallization has occurred in alloy under deformation temperature and high strain rate；And Mg-2.0Zn-0.3Zr-5.8Y magnesium alloy exists
Twin dynamic recrystallization will not occur at different distortion temperature and high strain rate, and compression deformation is risen to 0.913
When, attrition crushing has occurred in Mg-2.0Zn-0.3Zr-5.8Y magnesium alloy, hence, it can be determined that Mg-2.0Zn-0.3Zr-0.9Y magnesium
Alloy is at 300 DEG C of deformation temperature, rate of deformation 1s-1Twin dynamic recrystallization can occur；
(3) true stress-true strain curve (as shown in Figure 2) obtained according to thermal simulation experiment, is calculated Mg-2.0Zn-
The critical strain of twin dynamic recrystallization, the calculation method of the limit stress are as follows: according to hot pressing occur for 0.3Zr-0.9Y alloy
Data creating true stress-true strain curve obtained in contracting simulation test (σ-ε curve), asks single order to lead the curve using Origin
Numberθ-ε curve (as shown in Figure 2) is obtained, recycles θ to seek single order local derviation to σ, obtainsWith the pass of σ
System's figure (as shown in Figure 3), obtains the minimum value of ordinate (σ) from the relational graph, then obtains the corresponding abscissa of the minimum valueValue, as limit stress, can obtain Mg-2.0Zn-0.3Zr-0.9Y at 300 DEG C of deformation temperature, rate of deformation 1s-1Item
The critical strain that twin dynamic recrystallization occurs under part is 0.301, that is, magnesium alloy just takes place dynamic when reaching the deformation strain
State recrystallization；
(4) the crushing failure at high speed deformation technique of magnesium alloy is formulated: the low of twin dynamic recrystallization can occur in step (4)
Deformation temperature and high strain rate are fast/high-speed extrusion processing parameters, the stage before magnesium alloy extrusion to critical strain
Fast/high speed compression mushrooming deformation is carried out, continues to be squeezed and deformed after reaching critical strain, is full of magnesium alloy just entirely by squeezing
The enclosure space that cylinder, pressure ram and extrusion die are formed；Specifically: extrusion cylinder diameter is 85mm, length 500mm；Stick
It is 16mm that material, which squeezes mode diameter, and extrusion ratio is about 28.When hot compression test strain rate is 1s-1When, it is scaled pressure ram propulsion
Speed is about 0.45m/min, and the extrusion speed of extrusion die exit bar is 25m/min.To increase the twin in extrusion ingot
Density, the stage before magnesium alloy extrusion to critical strain carry out " Fast Compression mushrooming deformation " technique and (are similar to two to stress
Compression process, extruding rate 25m/min (i.e. rate of deformation be 2s-1, pressure ram speed is 1.8m/s)), deflection is about
Diameter is 70mm, length to enable extrusion ingot sufficiently to carry out compression mushrooming deformation by 33% (corresponding true strain is 0.301)
For 500mm blank it is upset at diameter be 85mm, length is 333mm (as shown in Figure 4), when pressure ram displacement about reaches
When 151mm, the upset stage is completed, and extrusion billet is full of the closing entirely formed by extrusion cylinder, pressure ram and extrusion die just
Space.
Determine the method that " Fast Compression mushrooming deformation " technique is completed are as follows: by taking embodiment 1 as an example, true strain 0.301, because
To should be -0.301 so being negative direction for compression.According to following calculation method: setting mushrooming deformation amount as x (mm), then ln (x/
500mm)=- 0.301, it acquires: x=e-0.301× 500=-150.5mm.Therefore, extrusion billet compression deformation is about 151mm,
Namely starting moving displacement (x) in extruder setting pressure ram is about 151mm, can alarm or suspend after reaching predeterminated position,
Indicate that " Fast Compression mushrooming deformation " technical process is completed.
By test, extrusion speed of step (4) the Mg-2.0Zn-0.3Zr-0.9Y alloy in extrusion die exit is reachable
To 12.5m/min.
Embodiment 2
A kind of method of high-speed extrusion magnesium alloy, with embodiment 1, difference is: in step (4), " the Fast Compression pier
Thick deformation " technique replaces with " high speed compression mushrooming deformation " technique, technological parameter are as follows: upset crushes rate is 25m/
Min (is converted into and squeezes muzzle velocity), and upset extruding rate after the completion is set as 21m/min, exports speed with the extruding of 21m/min
Degree is squeezed, and obtained extruded rod performance is as follows: extrusion speed reaches 21m/min, and tensile strength reaches 330MPa, is extended
Rate reaches 23%, and obtained extruded rod crystal grain is tiny, and comprehensive mechanical property is good (as shown in Figure 5).
The foregoing is merely preferred embodiment of the present application, are not intended to limit this application, for those skilled in the art
For member, various changes and changes are possible in this application.Within the spirit and principles of this application, it is made it is any modification,
Equivalent replacement, improvement etc., should be included within the scope of protection of this application.
Claims (10)
1. a kind of method of high-speed extrusion magnesium alloy, characterized by the following steps:
(1) crushing failure at high speed magnesium alloy composition range is designed by microalloying means；
(2) by the magnesium alloy cast in step (1) at as-cast magnesium alloy,
(3) through as-cast magnesium alloy in hot Compression Simulation experimental study step (2) at different distortion temperature and strain rate
Hot deformation behavior, then by observation microscopic structure, screening can occur twin dynamic under low deformation temperature and high strain rate
The magnesium alloy ingredient of state recrystallization；
(4) according to hot Compression Simulation test obtained in data be calculated the magnesium alloy that is filtered out in step (3) occur it is twin
The critical strain of dynamic recrystallization；
(5) fast/high-speed extrusion deformation technique of magnesium alloy is formulated: the low of twin dynamic recrystallization can occur in step (3)
Deformation temperature and high strain rate are fast/high-speed extrusion processing parameters, the stage before magnesium alloy extrusion to critical strain
Fast/high speed compression mushrooming deformation is carried out, continues to be squeezed and deformed after reaching critical strain, is full of magnesium alloy just entirely by squeezing
The enclosure space that cylinder, pressure ram and extrusion die are formed.
2. the method for high-speed extrusion magnesium alloy as described in claim 1, it is characterised in that: in step (1), the microalloying
Means are to add trace alloying element on the basis of the existing magnesium alloy trade mark and obtain.
3. the method for high-speed extrusion magnesium alloy as described in claim 1, it is characterised in that: in step (1), the microalloying
Means are as follows: with magnesium alloy be basic element, add trace alloying element and obtain.
4. the method for high-speed extrusion magnesium alloy as described in any one of claims 1-3, it is characterised in that: described in step (1)
Alloying element includes rare earth element, alkaline earth element.
5. the method for high-speed extrusion magnesium alloy as described in claim 1, it is characterised in that: described micro to add in step (1)
The content of the alloying element added is no more than 1.0%, but is not 0%；
Preferably, in step (2), as-cast magnesium alloy is obtained using water cooling semi-continuous casting method；
Preferably, in step (2), homogenizing annealing processing is carried out to as-cast magnesium alloy.
6. the method for high-speed extrusion magnesium alloy as described in claim 1, it is characterised in that: in step (3), the low deformation temperature
Degree refers to deformation temperature at 400 DEG C hereinafter, the high strain rate refers to strain rate in 1s-1More than；
Alternatively, the low deformation temperature refers to deformation temperature between 250-400 DEG C.
7. the method for high-speed extrusion magnesium alloy as described in claim 1, it is characterised in that: in step (4), the limit stress
Calculation method are as follows: according to hot Compression Simulation test obtained in data creating true stress-true strain curve (σ-ε curve), root
According to σ-ε curve, first derivative is soughtθ-ε curve is obtained, single order local derviation is asked to ε using θ, is obtainedWith
The relational graph of σ, obtains the minimum value of ordinate (σ) from the relational graph, then obtains the corresponding abscissa of the minimum value's
Value, as limit stress.
8. such as the method for the described in any item high-speed extrusion magnesium alloys of claim 1-7, it is characterised in that: in step (2), use
Water cooling semi-continuous casting method obtains as-cast magnesium alloy；Preferably, in step (2), homogenizing annealing is carried out to as-cast magnesium alloy
Processing.
9. the magnesium alloy prepared such as the method for the described in any item high-speed extrusion magnesium alloys of claim 1-8.
10. method and/or magnesium as claimed in claim 9 such as the described in any item high-speed extrusion magnesium alloys of claim 1-8
Application of the alloy in communications and transportation, textile machine, defence and military, aerospace field.
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| CN112588856A (en) * | 2020-12-22 | 2021-04-02 | 中北大学 | Preparation method of high-performance Cu-Ni-Al alloy plate strip |
| CN113343516A (en) * | 2021-05-14 | 2021-09-03 | 华中科技大学 | Method for eliminating critical deformation of powder superalloy PPB and determining extrusion process parameters |
| CN113802075A (en) * | 2021-10-27 | 2021-12-17 | 成都大学 | Preparation method of AZ31 magnesium alloy with high strength and ductility |
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| CN103898424A (en) * | 2014-03-27 | 2014-07-02 | 太原理工大学 | Method for refining magnesium alloy crystal grains |
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| CN103898424A (en) * | 2014-03-27 | 2014-07-02 | 太原理工大学 | Method for refining magnesium alloy crystal grains |
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| CN112588856A (en) * | 2020-12-22 | 2021-04-02 | 中北大学 | Preparation method of high-performance Cu-Ni-Al alloy plate strip |
| CN113343516A (en) * | 2021-05-14 | 2021-09-03 | 华中科技大学 | Method for eliminating critical deformation of powder superalloy PPB and determining extrusion process parameters |
| CN113802075A (en) * | 2021-10-27 | 2021-12-17 | 成都大学 | Preparation method of AZ31 magnesium alloy with high strength and ductility |
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