CN112481519B - Preparation method of high-damping CuAlMn shape memory alloy - Google Patents
Preparation method of high-damping CuAlMn shape memory alloy Download PDFInfo
- Publication number
- CN112481519B CN112481519B CN202011246267.0A CN202011246267A CN112481519B CN 112481519 B CN112481519 B CN 112481519B CN 202011246267 A CN202011246267 A CN 202011246267A CN 112481519 B CN112481519 B CN 112481519B
- Authority
- CN
- China
- Prior art keywords
- shape memory
- memory alloy
- damping
- cualmn
- cualmn shape
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
- C22C9/01—Alloys based on copper with aluminium as the next major constituent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/02—Compacting only
- B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- 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
- C22C1/06—Making non-ferrous alloys with the use of special agents for refining or deoxidising
-
- 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
- C22C1/10—Alloys containing non-metals
- C22C1/1005—Pretreatment of the non-metallic additives
-
- 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
- C22C1/10—Alloys containing non-metals
- C22C1/1036—Alloys containing non-metals starting from a melt
-
- 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
- C22C1/10—Alloys containing non-metals
- C22C1/1036—Alloys containing non-metals starting from a melt
- C22C1/1047—Alloys containing non-metals starting from a melt by mixing and casting liquid metal matrix composites
-
- 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
- C22C1/10—Alloys containing non-metals
- C22C1/1094—Alloys containing non-metals comprising an after-treatment
-
- 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
- C22F1/002—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
-
- 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
- C22F1/006—Resulting in heat recoverable alloys with a memory effect
-
- 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
- C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
- B22F2009/043—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by ball milling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Composite Materials (AREA)
- Fluid Mechanics (AREA)
- Manufacturing & Machinery (AREA)
- Powder Metallurgy (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention relates to a preparation method of a high-damping CuAlMn shape memory alloy. The method comprises the following steps: first, adding Cu51Zr14Mixing and ball-milling inoculant particles and multilayer graphene to obtain composite powder; secondly, carrying out cold pressing forming on the composite powder to obtain a prefabricated block; thirdly, adding Cu when the CuAlMn shape memory alloy is smelted51Zr14And (3) after the CuAlMn shape memory alloy is solidified, raising the temperature to 850-900 ℃, preserving the temperature, and then quenching in water at room temperature to obtain the high-damping CuAlMn shape memory alloy. The invention overcomes the defects that the damping performance is improved only by thinning crystal grains in the prior art, and the damping is improved by increasing the number of interfaces through the precipitation of the second phase, the size and the number of the second phase are difficult to control, and the like, so that the damping performance of the CuAlMn shape memory alloy is obviously improved.
Description
Technical Field
The technical scheme of the invention belongs to the technical field of composite materials, and particularly relates to a preparation method of a high-damping CuAlMn shape memory alloy.
Background
In the era of high-speed development of industrial technologies, various high-speed, high-efficiency and automatic mechanical devices are increasing day by day, the production and life of people are influenced by the problems of vibration, noise, fatigue fracture and the like which come with the mechanical devices, and the requirements of high-end fields such as aerospace, metallurgy, national defense and military industry on vibration and noise reduction are high all the time, so that functional materials capable of solving the problems of vibration and noise of various devices and apparatuses in modern industry, production and life from the source are urgently designed and developed. As a functional material, the CuAlMn shape memory alloy has wide application in the field of mechanical manufacturing due to good shape memory effect, abundant raw material sources and low manufacturing cost, and has considerable market prospect. However, the alloy still has the defects of easy occurrence of intergranular fracture due to coarse grains and low damping performance. Therefore, the key to improve the comprehensive performance of the alloy and further widen the application field is to refine the crystal grains by adopting a certain technical means.
Until now, the main means for grain refinement of metallic materials have mainly included rapid solidification, inoculant refinement, powder metallurgy, deformation heat treatment, and mechanical vibration and ultrasonic oscillation. The inoculant refining method is the most commonly used method for grain refining because the inoculant refining method is simple and easy to operate, has a refining effect more obvious than other methods, and the prepared product has the advantage of no size limitation. CN105568019B discloses a method for refining CuAlMn shape memory alloy crystal grains, which utilizes inoculant Cu51Zr14The modification and refinement function of the CuAlMn shape memory alloy refines the crystal grains of the CuAlMn shape memory alloy; CN107916348B discloses a preparation method of a fine-grain CuAlMn shape memory alloy, which is to refine grains of the CuAlMn shape memory alloy through a novel Al-based LaScB inoculant. However, the CuAlMn shape memory alloy prepared by the prior art can damp the CuAlMn shape memory alloy only through the grain refinement effectThe performance improvement is still limited. CN110527934B discloses a preparation method of a high-strength high-damping CuAlMn shape memory alloy, which comprises the steps of further refining the grain and the structure of the CuAlMn shape memory alloy through a groove rolling process, and separating out fine and dispersed second phases in the rolling process to increase the number of interfaces so as to improve the damping, but the operation process of the method is complex, and the size and the number of the separated out second phases in the rolling process are difficult to control. CN109266887B discloses a preparation method of a high-damping copper-based shape memory alloy, which is characterized in that rare earth elements Sc and metal elements Nb are added into a CuAlMn shape memory alloy, and then a second phase is precipitated through high-temperature aging of a mother phase to improve the damping of the CuAlMn shape memory alloy.
Disclosure of Invention
The invention aims to provide a preparation method of a high-damping CuAlMn shape memory alloy aiming at the defects in the prior art. The method combines ball milling treatment, cold pressing and medium-frequency induction melting technologies, and adds multilayer graphene in the CuAlMn shape memory alloy besides an inoculant, so that the defect that in the prior art, the damping performance is improved only by refining crystal grains, and when the damping is improved by increasing the interface number through precipitation of a second phase, the size and the number of the second phase are difficult to control is overcome, and the damping performance of the CuAlMn shape memory alloy is obviously improved.
The technical scheme of the invention is as follows:
a preparation method of a high-damping CuAlMn shape memory alloy comprises the following steps:
first step, preparation of Cu51Zr14Inoculant and multilayer graphene composite powder:
mixing Cu51Zr14Mechanically crushing an inoculant ingot into particles with the particle size of less than 200 mu m, mixing the particles with the multilayer graphene in proportion, then putting the particles into a ball milling tank, and carrying out ball milling treatment for 5-15 h at the rotating speed of 200-400 r/min by adopting a ball mill and taking absolute ethyl alcohol as a wet milling medium to obtain composite powder;
wherein, Cu51Zr14The mass ratio of the inoculant particles to the multilayer graphene is 10: 1-10: 2.5;
the thickness of the multilayer graphene is preferably 3-10 nm.
Second step, preparation of Cu51Zr14The inoculant and the multilayer graphene prefabricated block body:
placing the composite powder prepared in the step one in a vacuum drying oven, drying for 6-10 h, taking out, and cold-pressing and forming by adopting a hydraulic press, wherein the pressing pressure is 100-300 MPa, and the pressure maintaining time is 3-7 min, so that Cu is obtained51Zr14A prefabricated block of inoculant and multilayer graphene;
the vacuum drying condition is preferably that the air pressure is pumped to 5Pa, and the temperature is 60-100 ℃;
thirdly, preparing a high-damping CuAlMn shape memory alloy product:
according to the composition that in the CuAlMn shape memory alloy, Al accounts for 11.9 percent of the total mass of CuAlMn, Mn accounts for 2.5 percent of the total mass of CuAlMn, and the balance is Cu, the raw materials of pure Cu, pure Al and electrolytic Mn with required dosage are weighed; then, placing pure Cu in a graphite crucible of a medium-frequency induction heating furnace, heating until the Cu is molten, sequentially adding electrolytic Mn and pure Al, removing floating slag after the raw materials are completely molten and preserving heat for 2-5 min, then moving to a resistance furnace at 1090-1110 ℃ for preserving heat for 5-15 min, and then pressing Cu which is wrapped by copper foil and accounts for 1.1-1.25% of the total mass of the CuAlMn shape memory alloy into a bell jar51Zr14Stirring the inoculant and the prefabricated block of the multilayer graphene for 20-40 seconds, pouring into a mold, putting the CuAlMn shape memory alloy into a resistance furnace again after solidification, heating to 850-900 ℃, preserving heat for 10-12 min, and then putting into water at room temperature for quenching, thereby preparing the high-damping CuAlMn shape memory alloy.
According to the preparation method of the high-damping CuAlMn shape memory alloy, the ball mill adopted in ball milling treatment is an all-directional planetary ball mill, the adopted ball milling tank and the adopted grinding balls are made of stainless steel materials, the diameters of the grinding balls are 5mm, 8mm and 10mm, the mass ratio of the three grinding balls is 3:2:1, the ball-material ratio is 10:1, the ball milling treatment adopts a process of stopping the ball milling for 30min and alternately performing positive rotation and negative rotation.
According to the preparation method of the high-damping CuAlMn shape memory alloy, the room-temperature damping tan theta of the prepared high-damping CuAlMn shape memory alloy can reach 0.0558 at most.
The preparation method of the high-damping CuAlMn shape memory alloy relates to the preparation of Cu by adopting the CN105568019B technology51Zr14The materials and equipment for inoculating agents are well known in the art and the methods of operation involved are within the skill of the art.
The invention has the substantive characteristics that:
most of the previous researches are to improve the damping by adding an inoculant, refining alloy elements to form grains or precipitating a second phase by a heat treatment process to increase the interface density. The multilayer graphene has high mechanical damping and interface friction slip energy consumption capacity, and is very useful for improving the damping performance of the alloy, although the graphene is a hot addition substance, the graphene is not wet with a metal melt, and the graphene is difficult to be directly added into the metal melt, so that the graphene is rarely added into the copper-based shape memory alloy melt in the field so as to improve the damping performance.
The inventors have conducted extensive studies and found that Cu51Zr14The inoculant is brittle and can not react with carbon in graphene to lose refining effect, and then Cu is firstly subjected to an all-directional planetary ball mill51Zr14The inoculant is highly uniformly mixed with the multilayer graphene, and then cold-pressed into blocks, successfully with the help of Cu51Zr14The inoculant adds the multilayer graphene into the melt of the CuAlMn alloy, so that the problem that the graphene and the CuAlMn alloy are difficult to add due to obviously different specific gravity and poor wettability is solved. Thereby realizing Cu51Zr14The inoculant and the multilayer graphene play a role simultaneously, so that the damping performance of the CuAlMn alloy is greatly improved.
The adoption of an all-dimensional planetary ball mill in the preparation method comprises the step of carrying out ball milling on Cu in advance51Zr14The inoculant and the multilayer graphene are highly uniformThe method comprises the steps of uniformly mixing, cold pressing the mixed powder into blocks in advance, wrapping the blocks by using copper foil when the mixed powder is put into a melt, stirring immediately after the blocks are put into the melt and the like, thereby overcoming the prior technical difficulties. In this process, Cu51Zr14The inoculant plays two roles, namely grain refinement and successful introduction of multilayer graphene into an alloy melt.
The invention has the beneficial effects that:
compared with the prior art, the preparation method of the high-damping CuAlMn shape memory alloy has the prominent substantive characteristics and remarkable progress as follows:
(1) the invention introduces the ball milling treatment and cold pressing process in Cu51Zr14In the process of mixing the inoculant and the multilayer graphene, the adopted ball mill is an all-directional planetary ball mill, the adopted ball milling tank and the adopted grinding balls are made of stainless steel materials, the diameters of the grinding balls are 5mm, 8mm and 10mm, the mass ratio of the three grinding balls is 3:2:1, the ball-material ratio is 10:1, the ball milling treatment adopts a process of stopping the ball milling for 10min every 30min, and the forward rotation and the reverse rotation are alternately carried out, and absolute ethyl alcohol is added as a wet milling medium in the ball milling treatment process. The preferred ball mill and grinding balls with diameters and mass ratios are beneficial to preparing evenly dispersed Cu51Zr14Mixed powder of inoculant and graphene, the preferred pellet ratio favoring Cu51Zr14Crushing and uniformly refining inoculant particles; graphene sheets are uniformly dispersed and attached to Cu51Zr14The inoculant particle surface avoids the defect that graphene is easy to agglomerate and is difficult to disperse. And the preferred technology of stopping for 10min every 30min of ball milling and alternately carrying out positive and negative rotation and the adoption of a wet milling medium effectively avoid the defects of heating of a ball milling tank, powder oxidation and powder waste due to the loss of the adhered tank wall. Bulk Cu can be processed by the selected ball milling process51Zr14The inoculant is crushed into irregular flaky particles with the thickness of about 1 mu m, and a part of crushed multilayer graphene sheets are adhered to Cu51Zr14Particle surface of inoculant, due to Cu during ball milling51Zr14Part of fine particles generated by large brittleness are dispersed and included among the multilayer graphene sheet layers to formA sandwich structure, and then cold-press forming to obtain compact Cu51Zr14And (3) wrapping a precast block of an inoculant and multilayer graphene by using copper foil, and adding the wrapped precast block into a melt of the CuAlMn shape memory alloy. By adopting the series of measures, the difficult problem that the graphene is difficult to be directly and uniformly added into the CuAlMn shape memory alloy melt due to the fact that the specific gravities of the metal matrix and the graphene are obviously different and the metal matrix and the graphene are chemically incompatible and non-wetting is ingeniously overcome.
(2) The invention adds Cu into the CuAlMn shape memory alloy51Zr14Inoculant and multilayer graphene. In one aspect, Cu51Zr14The heterogeneous nucleation effect of the inoculant enables the crystal grains and the structure of the CuAlMn shape memory alloy to be refined, so that the number of interfaces (including interfaces among martensite, twin crystal interfaces, interfaces between a martensite phase and a parent phase in the phase transformation process and interfaces between inoculant particles and a matrix) is effectively increased. The interfaces can efficiently consume energy under an external alternating load, so that the CuAlMn shape memory alloy has high damping capacity. On the other hand, the multilayer graphene has high mechanical damping and interface friction slip energy consumption capacity, a large number of folded graphene-graphene interfaces are additionally generated in the ball milling process, and the damping performance of the CuAlMn shape memory alloy is further improved by the factors, so that the invention can obtain better damping capacity compared with the prior art CN105568019B and CN 107916348B. The damping value of the CuAlMn shape memory alloy prepared by the method of the invention at room temperature can reach 0.0558 to the maximum, while the damping value of the CuAlMn shape memory alloy prepared by the prior art CN105568019B at room temperature only reaches 0.0264 to the maximum, and the damping value of the CuAlMn shape memory alloy prepared by the CN107916348B at room temperature is 0.0400 to the maximum.
(3) The method has the advantages of common equipment, simple operation and easy realization of large-scale production.
(4) CN105568019B and CN107916348B are previous patents of the inventor of the invention, the damping is improved by adding inoculant to refine grains, the damping improving effect is still limited, and the requirement of high speed of mechanical equipment is not metHigh efficiency, intellectualization and automation, and the problem of vibration and noise reduction is urgently needed. CN109266887B and CN110527934B are patent applications of the present inventor in recent two years, and the damping capacity is further improved by precipitating second phase particles through high temperature aging and pass rolling processes on the basis of grain refinement to increase the number of interfaces, and both of the two measures for improving damping have the disadvantage that the size and number of the precipitated second phase particles are difficult to control. Therefore, the inventor team of the invention passes through a large number of hard experiments on the basis of the invention, and finally creatively adopts the ball milling treatment process to mix the multilayer graphene and the Cu through hard labor51Zr14Mixing and ball-milling inoculant to ensure that a part of crushed graphene sheets are adhered to Cu51Zr14Surface of inoculant particles during ball milling due to Cu51Zr14Part of fine particles generated by large brittleness are dispersed and mixed between graphene sheets to form a sandwich structure. After the two materials are added into the CuAlMn shape memory alloy, not only the crystal grains of the CuAlMn shape memory alloy are refined and the interface density is improved, but also the added multilayer graphene has high mechanical damping and interface friction slip energy consumption capability, and the graphene-graphene interface in a fold form generated in the ball milling process can further increase the interface energy consumption so as to obviously improve the damping performance of the alloy. The technical solutions for obtaining the present invention on the basis of the prior art CN105568019B and CN107916348B and CN109266887B and CN110527934B in combination with common general knowledge in the art or conventional technical means are in no way readily available to the skilled person.
CN110016589A 'a high-strength copper-nickel alloy material and a preparation method thereof', is that a large amount of net structures are formed by interaction of added graphene and other components, and the strength and toughness of the material are remarkably improved. CN109852841B 'A high-strength high-toughness graphene reinforced copper-based composite material and a pearl layer bionic preparation method thereof', is to improve the strength and toughness of the copper-based composite material by the bionic of a brick-mud-bridge structure of the pearl layer. The technical scheme provided by the invention is that an inoculant and multilayer graphene are added into the CuAlMn shape memory alloy simultaneously to improve the damping performance of the CuAlMn shape memory alloy through ball milling treatment, cold pressing and medium-frequency induction melting technology, so that the application requirements of vibration reduction and noise reduction are met.
The method of the invention is also suitable for improving the damping performance of other copper-based shape memory alloys.
The following examples will further demonstrate the outstanding substantive features and significant advances in the process of the present invention.
Detailed Description
Example 1
This example is a comparative example.
Preparing an unrefined CuAlMn shape memory alloy product:
according to the composition of CuAlMn shape memory alloy, Al accounts for 11.9% of the total mass of CuAlMn, Mn accounts for 2.5% of the total mass of CuAlMn, and the balance is Cu, the required amounts of pure Cu, pure Al and electrolytic Mn are weighed, then pure Cu is placed in a graphite crucible in a medium-frequency induction heating furnace, electrolytic Mn and pure Al are sequentially added after the temperature is raised to Cu melting, surface scum is rapidly skimmed after the raw materials are completely melted and heat preservation is carried out for 3min, then the raw materials are moved into a resistance furnace with the temperature of 1100 ℃ for heat preservation for 10min, then the raw materials are stirred for 30 s and poured into a steel mold, after the CuAlMn shape memory alloy is solidified, the raw materials are placed into the resistance furnace again and are raised to 900 ℃, the temperature is preserved for 10min, then the raw materials are put into water with the room temperature for quenching, and finally, the undifined CuAlMn shape memory alloy product with the damping values of 0.0108, 0.0101 and 0.0123 is prepared when the temperature is 35 ℃, 70 ℃ and 100 ℃.
Example 2
First step, preparation of Cu51Zr14Inoculant and multilayer graphene composite powder:
cu prepared from CN105568019B (prepared in the first step of examples 3-9 of the patent)51Zr14Mechanically crushing an inoculant ingot into particles with the particle size of less than 200 mu m, mixing the particles with a commercially available (WG 5, New Material science and technology Co., Ltd., Uygur lake Jikang) multilayer graphene with the lamella thickness of 3-10 nm according to the mass ratio of 10:2, and then filling the mixture into a ball according to the ball material mass ratio of 10:1In the milling tank, an omnibearing planetary ball mill is adopted to perform ball milling treatment for 15h by taking absolute ethyl alcohol (filling the milling tank to prevent air from entering) as a wet milling medium at the rotating speed of 200r/min to obtain Cu51Zr14A composite powder of inoculant and multilayer graphene;
second step, preparation of Cu51Zr14The inoculant and the multilayer graphene prefabricated block body:
placing the composite powder prepared in the step one in a vacuum drying oven, pumping the composite powder to 5Pa in the drying oven at the temperature of 100 ℃, drying for 6h, taking out, and carrying out cold press forming by adopting a hydraulic press at the pressing pressure of 100MPa for 7min to obtain Cu51Zr14A prefabricated block of inoculant and multilayer graphene;
thirdly, preparing a high-damping CuAlMn shape memory alloy product:
according to the composition of the CuAlMn shape memory alloy, Al accounts for 11.9% of the total mass of CuAlMn, Mn accounts for 2.5% of the total mass of CuAlMn, and the balance is Cu, the raw materials of pure Cu, pure Al and electrolytic Mn with required dosage are weighed. Then, placing pure Cu in a graphite crucible of a medium-frequency induction heating furnace, heating until the Cu is molten, sequentially adding electrolytic Mn and pure Al, rapidly skimming surface scum after the raw materials are completely molten and preserving heat for 2min, then moving to a resistance furnace at 1090 ℃ for preserving heat for 15min, and then pressing a copper foil-wrapped Cu which accounts for 1.2 percent of the total mass of the CuAlMn shape memory alloy into the resistance furnace by using a bell jar51Zr14Stirring a prefabricated block of an inoculant and multilayer graphene for 20 seconds, pouring the prefabricated block into a steel mold, putting the solidified CuAlMn shape memory alloy into a resistance furnace again after the solidification of the CuAlMn shape memory alloy, heating to 850 ℃, keeping the temperature for 12min, and then putting the solidified CuAlMn shape memory alloy into water at room temperature for quenching, thereby finally preparing a CuAlMn shape memory alloy product with damping values respectively reaching 0.0481, 0.0450 and 0.0417 at the temperature of 35 ℃, 70 ℃ and 100 ℃ (the damping performance is measured by adopting a single cantilever method by adopting a dynamic thermomechanical analyzer (DMA for short, the model is Q800, American TA instruments). By comparison, the damping values at 35 ℃ and 70 ℃ of the CuAlMn shape memory alloy product prepared in this example were 4.45 times the damping value at this temperature of the product prepared in example 1, and the damping value at 100 ℃ was 4.45 times that of the product prepared in example 1The damping value at this temperature is 3.39 times.
Example 3
First step, preparation of Cu51Zr14Inoculant and multilayer graphene composite powder:
cu prepared from CN105568019B51Zr14Mechanically crushing an inoculant ingot into particles with the particle size of less than 200 mu m, mixing the particles with commercially available multilayer graphene with the lamella thickness of 3-10 nm according to the mass ratio of 10:1, then filling the particles into a ball milling tank according to the ball mass ratio of 10:1, and performing ball milling treatment for 10 hours at the rotating speed of 300r/min by adopting an all-directional planetary ball mill and taking absolute ethyl alcohol as a wet milling medium to obtain Cu51Zr14A composite powder of inoculant and multilayer graphene;
second step, preparation of Cu51Zr14The inoculant and the multilayer graphene prefabricated block body:
placing the composite powder prepared in the step one in a vacuum drying oven, pumping the composite powder to 5Pa in the drying oven under the air pressure, setting the temperature to 80 ℃, taking out the composite powder after 8h, and carrying out cold press forming by adopting a hydraulic press, wherein the pressing pressure is 200MPa, and the pressure maintaining time is 5min, so as to obtain Cu51Zr14A prefabricated block of inoculant and multilayer graphene;
thirdly, preparing a high-damping CuAlMn shape memory alloy product:
according to the composition of the CuAlMn shape memory alloy, Al accounts for 11.9% of the total mass of CuAlMn, Mn accounts for 2.5% of the total mass of CuAlMn, and the balance is Cu, the raw materials of pure Cu, pure Al and electrolytic Mn with required dosage are weighed. Then, placing pure Cu in a graphite crucible of a medium frequency induction heating furnace, adding electrolytic Mn and pure Al in sequence after heating until the Cu is melted, rapidly skimming surface scum after the raw materials are completely melted and preserving heat for 3min, then moving the raw materials to a resistance furnace with the temperature of 1100 ℃ for preserving heat for 10min, and then pressing Cu which is wrapped by copper foil and accounts for 1.1 percent of the total mass of the CuAlMn shape memory alloy into the resistance furnace by using a bell jar51Zr14Stirring a prefabricated block body of an inoculant and multilayer graphene for 30 seconds, pouring the prefabricated block body into a steel mold, putting the prefabricated block body into a resistance furnace again after the CuAlMn shape memory alloy is solidified, heating to 900 ℃, preserving heat for 10min, and putting the prefabricated block body into water at room temperature for quenching, thereby finally obtaining the temperatureThe product is a CuAlMn shape memory alloy product with the damping values of 0.0369, 0.0326 and 0.0298 at 35 ℃, 70 ℃ and 100 ℃. By comparison, the damping values at 35 ℃ and 70 ℃ for the CuAlMn shape memory alloy product prepared in this example were 3.41 times and 3.22 times the damping value at this temperature for the product prepared in example 1, respectively, and the damping value at 100 ℃ was 2.42 times the damping value at this temperature for the product prepared in example 1.
Example 4
In this embodiment except for Cu in the first step51Zr14The inoculant particles and the commercially available multilayer graphene are mixed according to the mass ratio of 10:1.5, the addition amount of the prefabricated block in the third step is 1.15% of the total mass of the CuAlMn alloy, and the rest is the same as that in example 3.
The damping values of the CuAlMn shape memory alloy prepared by the embodiment can reach 0.0423, 0.0390 and 0.0356 respectively at the temperature of 35 ℃, 70 ℃ and 100 ℃. By comparison, the damping values at 35 ℃ and 70 ℃ for the CuAlMn shape memory alloy product prepared in this example were 3.91 times and 3.86 times, respectively, the damping value at 100 ℃ was 2.89 times the damping value at this temperature for the product prepared in example 1.
Example 5
In this example except for Cu in the first step51Zr14The inoculant particles and the commercially available multilayer graphene are mixed according to the mass ratio of 10:2, the addition amount of the prefabricated block in the third step is 1.2% of the total mass of the CuAlMn alloy, and the rest is the same as that in example 3.
The damping values of the CuAlMn shape memory alloy prepared by the embodiment can reach 0.0558, 0.0509 and 0.0446 respectively at the temperature of 35 ℃, 70 ℃ and 100 ℃. By comparison, the damping values at 35 ℃ and 70 ℃ for the CuAlMn shape memory alloy product prepared in this example were 5.16 times and 5.03 times the damping value at this temperature for the product prepared in example 1, respectively, and the damping value at 100 ℃ was 3.62 times the damping value at this temperature for the product prepared in example 1.
Example 6
In this example except for Cu in the first step51Zr14The mass ratio of the particles to the commercially available multi-layer graphene isThe mixture ratio of 10:2.5, the addition amount of the prefabricated block in the third step is 1.25% of the total mass of the CuAlMn alloy, and the other steps are the same as those of the embodiment 3.
The damping values of the CuAlMn shape memory alloy prepared by the embodiment can reach 0.0520, 0.0474 and 0.0432 respectively at the temperature of 35 ℃, 70 ℃ and 100 ℃. By comparison, the damping values at 35 ℃ and 70 ℃ for the CuAlMn shape memory alloy product prepared in this example were 4.81 times and 4.69 times the damping value at this temperature for the product prepared in example 1, respectively, and the damping value at 100 ℃ was 3.51 times the damping value at this temperature for the product prepared in example 1.
Example 7
First step, preparation of Cu51Zr14Inoculant and multilayer graphene composite powder:
cu prepared from CN105568019B51Zr14Mechanically crushing an inoculant ingot into particles with the particle size of less than 200 mu m, mixing the particles with commercially available multilayer graphene with the lamella thickness of 3-10 nm according to the mass ratio of 10:2, then filling the particles into a ball milling tank according to the ball material mass ratio of 10:1, and performing ball milling treatment for 5 hours by adopting an all-round planetary ball mill with absolute ethyl alcohol as a wet milling medium at the rotating speed of 400r/min to obtain Cu51Zr14A composite powder of inoculant and multilayer graphene;
second step, preparation of Cu51Zr14The inoculant and the multilayer graphene prefabricated block body:
placing the composite powder prepared in the step one in a vacuum drying oven, pumping the composite powder to 5Pa in the drying oven at the temperature of 60 ℃, taking out the composite powder after 10h, and carrying out cold press forming by adopting a hydraulic press at the pressing pressure of 300MPa for 3min to obtain Cu51Zr14A prefabricated block of inoculant and multilayer graphene;
thirdly, preparing a high-damping CuAlMn shape memory alloy product:
according to the composition of the CuAlMn shape memory alloy, Al accounts for 11.9% of the total mass of CuAlMn, Mn accounts for 2.5% of the total mass of CuAlMn, and the balance is Cu, the raw materials of pure Cu, pure Al and electrolytic Mn with required dosage are weighed. Then, placing pure Cu in a graphite crucible of a medium-frequency induction heating furnace, and heating until the Cu is moltenAdding electrolytic Mn and pure Al, melting the raw materials, keeping the temperature for 5min, rapidly skimming the surface scum, transferring to a resistance furnace at 1110 ℃, keeping the temperature for 5min, and pressing Cu coated by copper foil and accounting for 1.2% of the total mass of the CuAlMn shape memory alloy into the furnace by using a bell jar51Zr14Stirring a prefabricated block body of an inoculant and multilayer graphene for 40 seconds, pouring the prefabricated block body into a steel mold, putting the solidified CuAlMn shape memory alloy into a resistance furnace again after the solidification of the CuAlMn shape memory alloy, heating to 880 ℃, preserving heat for 11min, and then putting the solidified CuAlMn shape memory alloy into water at room temperature for quenching, thereby finally preparing the CuAlMn shape memory alloy products with damping values respectively reaching 0.0454, 0.0422 and 0.0407 at the temperature of 25 ℃, 70 ℃ and 100 ℃. By comparison, the damping values at 35 ℃ and 70 ℃ for the CuAlMn shape memory alloy product prepared in this example were 4.20 times and 4.17 times the damping value at this temperature for the product prepared in example 1, respectively, and the damping value at 100 ℃ was 3.30 times the damping value at this temperature for the product prepared in example 1.
Table 1 shows the damping properties at 35 deg.C, 70 deg.C and 100 deg.C of the CuAlMn shape memory alloys prepared in examples 1-7.
TABLE 1
As can be seen from Table 1, the damping value of the CuAlMn shape memory alloy prepared by the method of the invention is significantly improved compared with the damping value of the CuAlMn shape memory alloy prepared by the prior art. In particular, the damping values of the CuAlMn shape memory alloys prepared in examples 5 and 6 at 35 ℃ are respectively increased from 0.0108 to 0.0558 and 0.0520 of the unrefined CuAlMn shape memory alloy prepared in example 1, and respectively increased to 5.16 times and 4.81 times; the damping values of the CuAlMn shape memory alloys produced in examples 5 and 6 increased from 0.0101 and 0.0123 of the unrefined CuAlMn shape memory alloy produced in example 1 to 0.0509 and 0.0446 (5.03-fold and 3.62-fold, respectively), and 0.0474 and 0.0432 (4.69-fold and 3.51-fold, respectively), at 70 ℃ and 100 ℃. The analysis shows that the invention adopts an omnibearing planetary ball mill to pre-align Cu51Zr14InoculantMixing with multi-layer graphene, ball milling to make part of crushed graphene sheets adhere to Cu51Zr14Inoculant the surface of the flaky particles, and during the ball milling process due to Cu51Zr14Part of fine particles generated by large brittleness are dispersed and included among the sheets of graphene to form a sandwich structure, so that Cu is successfully utilized51Zr14The inoculant uniformly adds the graphene to the melt of the CuAlMn shape memory alloy. Cu51Zr14The inoculant is added simultaneously with the graphene, on the one hand, Cu51Zr14The heterogeneous nucleation effect of the inoculant can effectively refine grains and tissues of the CuAlMn shape memory alloy, so that the number of interfaces (including interfaces between martensite and twin crystal, interfaces between martensite and a parent phase in the phase transformation process and interfaces between inoculant particles and a matrix) is remarkably increased, and the interfaces can efficiently consume energy under an external alternating load, so that the CuAlMn shape memory alloy has high damping capacity. On the other hand, the multilayer graphene has high mechanical damping and interface friction sliding energy consumption capacity, a large number of graphene-graphene interfaces in a fold form are additionally generated in the ball milling process, and the damping performance of the CuAlMn shape memory alloy is further improved by the factors, so that the damping capacity of the prepared CuAlMn shape memory alloy product is remarkably improved.
The invention is not the best known technology.
Claims (4)
1. A preparation method of a high-damping CuAlMn shape memory alloy is characterized by comprising the following steps:
first step, preparation of Cu51Zr14Inoculant and multilayer graphene composite powder:
mixing Cu51Zr14Mechanically crushing an inoculant ingot into particles with the particle size of less than 200 mu m, mixing the particles with the multilayer graphene in proportion, then putting the particles into a ball milling tank, and carrying out ball milling treatment for 5-15 h at the rotating speed of 200-400 r/min by adopting a ball mill and taking absolute ethyl alcohol as a wet milling medium to obtain composite powder;
wherein, Cu51Zr14The mass ratio of the inoculant particles to the multilayer graphene is 10: 1-10: 2.5;
second step, preparation of Cu51Zr14The inoculant and the multilayer graphene prefabricated block body:
placing the composite powder prepared in the step one in a vacuum drying oven, drying for 6-10 h, taking out, and cold-pressing and forming by adopting a hydraulic press, wherein the pressing pressure is 100-300 MPa, and the pressure maintaining time is 3-7 min, so that Cu is obtained51Zr14A prefabricated block of inoculant and multilayer graphene;
thirdly, preparing a high-damping CuAlMn shape memory alloy product:
according to the composition that in the CuAlMn shape memory alloy, Al accounts for 11.9 percent of the total mass of CuAlMn, Mn accounts for 2.5 percent of the total mass of CuAlMn, and the balance is Cu, the raw materials of pure Cu, pure Al and electrolytic Mn with required dosage are weighed; then, placing pure Cu in a graphite crucible of a medium-frequency induction heating furnace, heating until the Cu is molten, sequentially adding electrolytic Mn and pure Al, removing floating slag after the raw materials are completely molten and preserving heat for 2-5 min, then moving to a resistance furnace at 1090-1110 ℃ for preserving heat for 5-15 min, and then pressing Cu which is wrapped by copper foil and accounts for 1.1-1.25% of the total mass of the CuAlMn shape memory alloy into a bell jar51Zr14Stirring a prefabricated block of an inoculant and multilayer graphene for 20-40 seconds, pouring the prefabricated block into a mold, putting the solidified CuAlMn shape memory alloy into a resistance furnace again after solidification, heating to 850-900 ℃, preserving heat for 10-12 min, and then putting the solidified CuAlMn shape memory alloy into water at room temperature for quenching to obtain the high-damping CuAlMn shape memory alloy;
the thickness of the multilayer graphene sheet layer is 3-10 nm.
2. The method of claim 1, wherein the vacuum drying is performed at 60-100 ℃ under a pressure of 5 Pa.
3. The method for preparing a high damping CuAlMn shape memory alloy according to claim 1, wherein the ball mill used in the ball milling process is an all-directional planetary ball mill, the ball milling tank and the milling balls used in the ball milling process are made of stainless steel, the diameters of the milling balls are 5mm, 8mm and 10mm, the mass ratio of the three milling balls is 3:2:1, the ball-to-material ratio is 10:1, the ball milling process is performed by stopping the ball milling for 30min and alternately performing forward rotation and reverse rotation.
4. The method of claim 1, wherein the high damping CuAlMn shape memory alloy has a room temperature damping tan θ of 0.0558.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011246267.0A CN112481519B (en) | 2020-11-10 | 2020-11-10 | Preparation method of high-damping CuAlMn shape memory alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011246267.0A CN112481519B (en) | 2020-11-10 | 2020-11-10 | Preparation method of high-damping CuAlMn shape memory alloy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112481519A CN112481519A (en) | 2021-03-12 |
| CN112481519B true CN112481519B (en) | 2021-10-08 |
Family
ID=74929091
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011246267.0A Active CN112481519B (en) | 2020-11-10 | 2020-11-10 | Preparation method of high-damping CuAlMn shape memory alloy |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112481519B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113119545B (en) * | 2021-04-20 | 2022-05-10 | 河北工业大学 | Ultrahigh-damping and high-strength metal-based composite material and preparation method thereof |
| CN113426996B (en) * | 2021-06-11 | 2022-10-11 | 武汉大学 | Shape memory alloy-based composite intelligent material and preparation method thereof |
| CN114226719B (en) * | 2021-11-12 | 2023-10-03 | 深圳前海石墨烯产业有限公司 | Graphene manganese copper-based damping material powder, alloy damping material, preparation method and application |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008054356A2 (en) * | 2005-08-15 | 2008-05-08 | The University Of Akron | Nanoporous materials for use in intelligent systems |
| CN102925741A (en) * | 2012-11-08 | 2013-02-13 | 镇江中孚复合材料有限公司 | Copper base solid self-lubricating composite material and method for preparing the same |
| KR20130054843A (en) * | 2011-11-17 | 2013-05-27 | 삼성에스디아이 주식회사 | Silicon based shape memory alloy anode active material, anode active material composition including the same, rechargeable lithium battery including the same, and preparation method for the same |
| CN105568019A (en) * | 2016-02-24 | 2016-05-11 | 河北工业大学 | Refining method for CuAlMn shape memory alloy grains |
| CN107805311A (en) * | 2016-09-09 | 2018-03-16 | 翁秋梅 | A kind of dynamic aggregation thing and its application with hybrid cross-linked network |
| CN108746646A (en) * | 2018-05-08 | 2018-11-06 | 东莞市佳乾新材料科技有限公司 | A kind of preparation process of tinbase marmem powder for 3D printing |
| CN109277571A (en) * | 2018-09-25 | 2019-01-29 | 中南大学 | A kind of therlo/polymer/carbon nano-tube damping material and preparation method |
| CN110527934B (en) * | 2019-10-14 | 2020-08-04 | 河北工业大学 | Preparation method of high-strength high-damping CuAlMn shape memory alloy |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9096034B2 (en) * | 2011-04-12 | 2015-08-04 | Powdermet, Inc. | Syntactic metal matrix materials and methods |
-
2020
- 2020-11-10 CN CN202011246267.0A patent/CN112481519B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008054356A2 (en) * | 2005-08-15 | 2008-05-08 | The University Of Akron | Nanoporous materials for use in intelligent systems |
| KR20130054843A (en) * | 2011-11-17 | 2013-05-27 | 삼성에스디아이 주식회사 | Silicon based shape memory alloy anode active material, anode active material composition including the same, rechargeable lithium battery including the same, and preparation method for the same |
| CN102925741A (en) * | 2012-11-08 | 2013-02-13 | 镇江中孚复合材料有限公司 | Copper base solid self-lubricating composite material and method for preparing the same |
| CN105568019A (en) * | 2016-02-24 | 2016-05-11 | 河北工业大学 | Refining method for CuAlMn shape memory alloy grains |
| CN107805311A (en) * | 2016-09-09 | 2018-03-16 | 翁秋梅 | A kind of dynamic aggregation thing and its application with hybrid cross-linked network |
| CN108746646A (en) * | 2018-05-08 | 2018-11-06 | 东莞市佳乾新材料科技有限公司 | A kind of preparation process of tinbase marmem powder for 3D printing |
| CN109277571A (en) * | 2018-09-25 | 2019-01-29 | 中南大学 | A kind of therlo/polymer/carbon nano-tube damping material and preparation method |
| CN110527934B (en) * | 2019-10-14 | 2020-08-04 | 河北工业大学 | Preparation method of high-strength high-damping CuAlMn shape memory alloy |
Non-Patent Citations (1)
| Title |
|---|
| 石墨颗粒/CuAlMn形状记忆合金复合材料中的位错内耗峰;孙蔚等;《物理学报》;20070228;第56卷(第2期);第2.1节和第4节 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112481519A (en) | 2021-03-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112481519B (en) | Preparation method of high-damping CuAlMn shape memory alloy | |
| CN112899531B (en) | High-entropy alloy particle reinforced aluminum-based composite material and magnetic field auxiliary preparation method | |
| CN101463442A (en) | Casting magnesium alloy containing Ag and heavy rare earth and preparation thereof | |
| CN110885944B (en) | Aluminum-copper alloy welding wire suitable for wire material additive manufacturing | |
| CN101338389A (en) | Preparation process of rare-earth copper alloy material for preparing integral dispersion copper | |
| CN109468496B (en) | Heat-resistant die-casting aluminum alloy and preparation method thereof | |
| CN115261686B (en) | 3D printing aluminum-magnesium alloy powder and preparation method and application thereof | |
| CN111996407B (en) | Preparation method of graphene reinforced aluminum matrix composite material with dual-mode structure | |
| CN114672686B (en) | Preparation method of additional nano-particle reinforced cast aluminum-lithium alloy | |
| CN115125423A (en) | High-strength high-formability magnesium-lithium alloy and preparation method and application thereof | |
| Ji et al. | Influence of characteristic parameters of SiC reinforcements on mechanical properties of AlSi10Mg matrix composites by powder metallurgy | |
| CN109266893B (en) | Method for reinforcing magnesium alloy composite material by coating zinc oxide graphene | |
| CN110983081A (en) | Method for preparing ultra-low oxygen cupronickel by adopting vacuum melting equipment | |
| WO2012065455A1 (en) | Aluminum-zirconium-titanium-carbon crystal grain refiner for magnesium and magnesium alloys and preparation method thereof | |
| CN116426825B (en) | High-toughness die steel material, preparation method and die prepared by using same | |
| CN110527934B (en) | Preparation method of high-strength high-damping CuAlMn shape memory alloy | |
| CN116121581B (en) | Particle reinforced aluminum-based composite intermediate alloy, aluminum-based composite material and preparation methods thereof | |
| CN107739870A (en) | A kind of preparation method of SiC reinforcement high Al-Zn base composite | |
| CN115029596A (en) | Self-assembly nanosheet material for PCB (printed circuit board) grade shielding case material and preparation method thereof | |
| CN111286634B (en) | Preparation method of cerium oxide-coated graphene oxide aluminum material semi-solid blank | |
| CN105903953B (en) | A kind of powder used in metallurgy stainless steel/graphene composite powder and preparation method thereof | |
| CN115029590A (en) | High-rigidity high-strength high-temperature-resistant aluminum-based composite material and preparation method thereof | |
| CN111020279B (en) | High-strength high-conductivity copper-graphite composite material and preparation method thereof | |
| CN113430446A (en) | High-entropy alloy with super-strong deformability, preparation method and plate prepared from high-entropy alloy | |
| CN111575523A (en) | Preparation method of AZ91 alloy for vehicle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |