Memory alloy based on modified rare earth base as well as smelting process and preparation method thereof

Abstract

The invention relates to a memory alloy based on a modified rare earth base and a smelting process and a preparation method of the memory alloy, and belongs to the technical field of memory alloys, and the memory alloy based on the modified rare earth base is prepared from the following raw materials in parts by weight: 15 parts of Mn, 5 parts of Si, 0.15-0.25 part of C, 3-9 parts of Cr, 2-6 parts of Ni, 0-0.2 part of rare earth particles and 64.55-74.85 parts of Fe. The rare earth particles are added into the prepared memory alloy, so that the volume of Ce particles, the hardness of quenched Ce and the frictional resistance after the surface is corroded by soft acid are relatively increased, and the Ce particles are mixed with other raw materials more uniformly, so that the internal Ce is distributed more uniformly when the memory alloy is forged, and the service life of the memory alloy is prolonged. Therefore, segregation of Ce in the memory alloy is avoided as much as possible, and the overall performance of the memory alloy is ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of memory alloy, and particularly relates to a modified rare earth-based memory alloy and a smelting process and preparation method thereof. BACKGROUND

[0002] A memory alloy is a martensitic phase change alloy with regular atomic arrangement and a volume change of less than 0.5%, which can change its shape when subjected to a specific external stimulus and restore to the original shape after the stimulus is removed. This material has more than one million recovery functions, and is therefore called a memory alloy.

[0003] At present, rare earth Ce (cerium) is added to the memory alloy to refine the grain, increase the phase change temperature, improve the memory effect and mechanical properties. However, the content of Ce is relatively low in the smelting and forging process of the memory alloy, so that the proportion of Ce in the numerous raw materials is low. Therefore, it is not easy to mix uniformly during the mixing process of Ce and numerous raw materials, which leads to composition segregation of Ce in the memory alloy smelted and forged, and affects the overall performance of the memory alloy. SUMMARY

[0004] The purpose of the present application is to provide a modified rare earth-based memory alloy and a smelting process and preparation method thereof to solve the above problems.

[0005] The application achieves the above-mentioned purpose through the following technical solutions:

[0006] The application provides a modified rare earth-based memory alloy, and the preparation raw materials of the modified rare earth-based memory alloy include 15 parts of Mn, 5 parts of Si, 0.15-0.25 parts of C, 3-9 parts of Cr, 2-6 parts of Ni, 0-0.2 parts of rare earth microparticles, and 64.55-74.85 parts of Fe.

[0007] As a further optimization scheme of the application, the specific preparation method of Mn is as follows: (1) Mn blocks are made into Mn particles using 3D printing technology, and the diameter of the Mn particles is 0.01-0.03 mm; (2) the Mn particles are etched to etch 3-6 hemispherical grooves with a diameter of 0.001-0.003 mm on the surface of the Mn particles;

[0008] The specific preparation method of Si is as follows: (1) Si blocks are made into Si particles using 3D printing technology, and the diameter of the Si particles is 0.001-0.003 mm; (2) the Si particles are etched to etch 3-6 hemispherical grooves with a diameter of 0.0001-0.0003 mm on the surface of the Si particles;

[0009] The specific preparation method of the C is: (1) the C block is made into C particles by using 3D printing technology, and the diameter of the C particles is 0.00001-0.00003 mm;

[0010] The specific preparation method of the Cr is: (1) the Cr block is made into Cr particles by using 3D printing technology, and the diameter of the Cr particles is 0.0001-0.0003 mm; (2) the Mn particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00001-0.00003 mm are etched on the surface of the Mn particles;

[0011] The specific preparation method of the Ni is: (1) the Ni block is made into Ni particles by using 3D printing technology, and the diameter of the Ni particles is 0.0001-0.0003 mm; (2) the Ni particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00001-0.00003 mm are etched on the surface of the Ni particles;

[0012] The specific preparation method of the Fe is: (1) the Fe block is made into Fe particles by using 3D printing technology, and the diameter of the Fe particles is 0.1-0.3 mm; (2) the Fe particles are etched, and 3-6 hemispherical grooves with a diameter of 0.01-0.03 mm are etched on the surface of the Fe particles.

[0013] As a further optimization scheme of the application, the specific preparation method of the rare earth microparticle is: (1) the Ce block is made into a hollow Ce particle by using 3D printing technology, the outer diameter of the Ce particle is 0.1-0.3 mm, and the inner diameter of the Ce particle is 0.09-0.29 mm; (2) the Ce particle is heated at high temperature, the heating temperature is controlled to be 600-790 DEG C, the first heating time is controlled to be 20-40 min, and the heating number is controlled to be 1-6 times; (3) the Ce particle is soaked in a weak acid solution, the temperature of the weak acid solution is controlled to be 40-60 DEG C, and the time is controlled to be 200-300 h; (4) the Ce particle is taken out from the weak acid solution and naturally dried to obtain a rare earth microparticle.

[0014] As a further optimization scheme of the application, the mass ratio of the Ce particle to the weak acid solution is 1:30.

[0015] As a further optimization scheme of the application, the weak acid solution is an acetic acid solution or a carbonic acid solution.

[0016] The preparation method of the smelting process of the modified rare earth-based memory alloy above comprises the following steps:

[0017] S1, the Mn, Si, C, Cr, Ni, rare earth microparticle and Fe are uniformly stirred, the stirring time is controlled to be 30-50 min, and the stirring speed is controlled to be 20-30 r / min, to obtain a raw material mixture;

[0018] S2, using a medium frequency induction melting furnace to smelt the raw material mixture, during smelting, after the raw material is melted, heat preservation for 20-40 min, to obtain a mixed liquid;

[0019] S3, using a metal mold to place, cool, shape and demold the mixed liquid, to obtain an ingot;

[0020] S4, homogenizing treatment is carried out on the ingot, the control time is 12h, and the control temperature is 1200 DEG C;

[0021] S5, the cap mouth and the outer skin of the ingot after S4 treatment are cut off, and the ingot is hot forged into a rectangular material with a length of 35mm and a width of 30mm and a round bar material with a diameter of 40mm, the initial forging temperature in hot forging is 1050 DEG C, and the final forging temperature is not lower than 900 DEG C;

[0022] S6, stress relief annealing treatment is carried out on the alloy after S5 forging, the control time is 24h, and the control temperature is 800 DEG C, to obtain a memory alloy based on a modified rare earth base.

[0023] The memory alloy prepared by the method has the advantages that the memory alloy is added with rare earth microparticles, the volume of Ce particles, the hardness of Ce after quenching and the frictional resistance after soft acid corrosion of the surface are relatively increased, so that the Ce particles are mixed more uniformly with other raw materials, and therefore, the internal Ce distribution of the memory alloy is more uniform when the memory alloy is forged, so that the composition segregation of Ce in the memory alloy is avoided as much as possible, and the overall performance of the memory alloy is ensured. DETAILED DESCRIPTION

[0024] It is necessary to point out here that the following detailed description is only used to further illustrate the application, and cannot be understood as limiting the protection scope of the application, and the skilled in the art can make some non-essential improvements and adjustments to the application according to the above application content.

[0025] I. Materials

[0026] The method used in the application is a conventional method known by those skilled in the art, and the reagents and materials used are commercially available products, unless otherwise specified.

[0027] (1) in the application,

[0028] In the application, Mn (manganese), Si (silicon), C (carbon), Cr (chromium), Ni (nickel) and Fe (iron) are used.

[0029] II. Embodiments

[0030] Embodiment 1

[0031] A modified rare earth-based memory alloy, the preparation raw materials of the modified rare earth-based memory alloy include, by weight: 15 parts of Mn, 5 parts of Si, 0.15 parts of C, 3 parts of Cr, 2 parts of Ni, 64.55 parts of Fe;

[0032] The above-mentioned modified rare earth-based memory alloy smelting process preparation method, comprising the following steps:

[0033] Mn: (1) Mn block is made into Mn particles by 3D printing technology, and the diameter of the Mn particles is 0.01 mm; (2) the Mn particles are etched to etch 3 hemispherical grooves with a diameter of 0.001 mm on the surface of the Mn particles;

[0034] Si: (1) Si block is made into Si particles by 3D printing technology, and the diameter of the Si particles is 0.001 mm; (2) the Si particles are etched to etch 3 hemispherical grooves with a diameter of 0.0001 mm on the surface of the Si particles;

[0035] C: (1) C block is made into C particles by 3D printing technology, and the diameter of the C particles is 0.00001 mm;

[0036] Cr: (1) Cr block is made into Cr particles by 3D printing technology, and the diameter of the Cr particles is 0.0001 mm; (2) the Mn particles are etched to etch 3 hemispherical grooves with a diameter of 0.00001 mm on the surface of the Mn particles;

[0037] Ni: (1) Ni block is made into Ni particles by 3D printing technology, and the diameter of the Ni particles is 0.0001 mm; (2) the Ni particles are etched to etch 3 hemispherical grooves with a diameter of 0.00001 mm on the surface of the Ni particles;

[0038] Fe: (1) Fe block is made into Fe particles by 3D printing technology, and the diameter of the Fe particles is 0.1 mm; (2) the Fe particles are etched to etch 3 hemispherical grooves with a diameter of 0.1 mm on the surface of the Fe particles;

[0039] Rare earth microparticles: (1) a Ce block is made into a hollow Ce particle by using a 3D printing technology, the outer diameter of the Ce particle is 0.1 mm, and the inner diameter of the Ce particle is 0.09 mm; (2) the Ce particle is heated at a high temperature, the heating temperature is controlled to be 600 DEG C, the first heating time is controlled to be 20 min, and the heating number is controlled to be 1; (3) the Ce particle is soaked in a carbonic acid solution (the mass ratio of the Ce particle to the carbonic acid solution is 1:30), the carbonic acid solution temperature is controlled to be 40 DEG C, and the time is controlled to be 200 h; (4) the Ce particle is taken out from the carbonic acid solution and naturally dried to obtain rare earth microparticles;

[0040] Mn, Si, C, Cr, Ni, rare earth microparticles and Fe are uniformly stirred, the time is controlled to be 30 min, and the stirring speed is controlled to be 20 r / min to obtain a raw material mixture;

[0041] The raw material mixture is melted by using a medium frequency induction melting furnace, and the mixture is obtained after the raw material is melted and kept for 20 min;

[0042] The mixture is placed, cooled, shaped and demolded by using a metal mold to obtain an ingot;

[0043] The ingot is subjected to homogenization treatment, the time is controlled to be 12 h, and the temperature is controlled to be 1200 DEG C;

[0044] The ingot after the above treatment is cut off the cap and the outer skin, and is respectively hot forged into a rectangular material with a length of 35 mm and a width of 30 mm and a round bar material with a diameter of 40 mm, and the initial forging temperature in the hot forging is 1050 DEG C, and the final forging temperature is not lower than 900 DEG C;

[0045] The alloy after the above forging is subjected to stress relief annealing treatment, the time is controlled to be 24 h, and the temperature is controlled to be 800 DEG C to obtain a modified rare earth-based memory alloy.

[0046] Example 2

[0047] A modified rare earth-based memory alloy, the preparation raw materials of the modified rare earth-based memory alloy include: 15 parts of Mn, 5 parts of Si, 0.2 parts of C, 6 parts of Cr, 4 parts of Ni, 0.1 parts of rare earth microparticles, and 69.7 parts of Fe by weight;

[0048] The above preparation method of the melting process of the modified rare earth-based memory alloy includes the following steps:

[0049] Mn: (1) an Mn block is made into an Mn particle by using a 3D printing technology, and the diameter of the Mn particle is 0.02 mm; (2) the Mn particle is subjected to etching treatment, and 5 hemispherical grooves with a diameter of 0.002 mm are etched on the surface of the Mn particle;

[0050] Si: (1) Si block is made into Si particles by using 3D printing technology, and the diameter of the Si particles is 0.002 mm; (2) the Si particles are etched, and 5 hemispherical grooves with a diameter of 0.0002 mm are etched on the surface of the Si particles;

[0051] C: (1) C block is made into C particles by using 3D printing technology, and the diameter of the C particles is 0.00002 mm;

[0052] Cr: (1) Cr block is made into Cr particles by using 3D printing technology, and the diameter of the Cr particles is 0.0002 mm; (2) the Mn particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00002 mm are etched on the surface of the Mn particles;

[0053] Ni: (1) Ni block is made into Ni particles by using 3D printing technology, and the diameter of the Ni particles is 0.0002 mm; (2) the Ni particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00002 mm are etched on the surface of the Ni particles;

[0054] Fe: (1) Fe block is made into Fe particles by using 3D printing technology, and the diameter of the Fe particles is 0.2 mm; (2) the Fe particles are etched, and 3-6 hemispherical grooves with a diameter of 0.02 mm are etched on the surface of the Fe particles;

[0055] Rare earth microparticles: (1) Ce block is made into hollow Ce particles by using 3D printing technology, and the outer diameter of the Ce particles is 0.2 mm and the inner diameter of the Ce particles is 0.19 mm; (2) the Ce particles are heated at a high temperature, the heating temperature is controlled to be 695℃, the first heating time is controlled to be 30 min, and the heating number is controlled to be 4 times; (3) the Ce particles are soaked in a carbonic acid solution (the mass ratio of the Ce particles to the carbonic acid solution is 1:30), the temperature of the carbonic acid solution is controlled to be 50℃, and the time is controlled to be 250 h; (4) the Ce particles are taken out from the carbonic acid solution and naturally dried to obtain rare earth microparticles;

[0056] The Mn, Si, C, Cr, Ni, rare earth microparticles and Fe are uniformly stirred, the stirring time is controlled to be 40 min, and the stirring speed is controlled to be 25 r / min to obtain a raw material mixture;

[0057] The raw material mixture is melted by using a medium frequency induction melting furnace, and after the raw material is melted, the temperature is kept for 30 min to obtain a mixed liquid;

[0058] The mixed liquid is placed, cooled, formed and demolded by using a metal mold to obtain an ingot;

[0059] The ingot is subjected to homogenization treatment, and the time is controlled to be 12 h and the temperature is controlled to be 1200℃;

[0060] The treated ingot is cut off the cap, cut off the skin, and hot forged into a 35mm*30mm rectangular square material and a Ф40mm round bar material, respectively, with an initial forging temperature of 1050℃ and a final forging temperature of no less than 900℃ in the hot forging;

[0061] The forged alloy is subjected to stress relief annealing treatment, with a control time of 24h and a control temperature of 800℃, to obtain a modified rare earth-based memory alloy.

[0062] Embodiment 3

[0063] A modified rare earth-based memory alloy, the preparation raw materials of the modified rare earth-based memory alloy include, by weight: 15 parts of Mn, 5 parts of Si, 0.25 parts of C, 9 parts of Cr, 6 parts of Ni, 0.2 parts of Ce, and 74.85 parts of Fe.

[0064] The above-mentioned preparation method of the melting process of the modified rare earth-based memory alloy includes the following steps:

[0065] Mn: (1) Mn blocks are made into Mn particles using 3D printing technology, with a diameter of 0.03mm; (2) Mn particles are subjected to etching treatment, with 6 hemispherical grooves with a diameter of 0.003mm etched on the surface of the Mn particles;

[0066] Si: (1) Si blocks are made into Si particles using 3D printing technology, with a diameter of 0.003mm; (2) Si particles are subjected to etching treatment, with 3-6 hemispherical grooves with a diameter of 0.0003mm etched on the surface of the Si particles;

[0067] C: (1) C blocks are made into C particles using 3D printing technology, with a diameter of 0.00003mm;

[0068] Cr: (1) Cr blocks are made into Cr particles using 3D printing technology, with a diameter of 0.0003mm; (2) Mn particles are subjected to etching treatment, with 6 hemispherical grooves with a diameter of 0.00003mm etched on the surface of the Mn particles;

[0069] Ni: (1) Ni blocks are made into Ni particles using 3D printing technology, with a diameter of 0.0003mm; (2) Ni particles are subjected to etching treatment, with 6 hemispherical grooves with a diameter of 0.00003mm etched on the surface of the Ni particles;

[0070] Fe: (1) Fe blocks are made into Fe particles using 3D printing technology, with a diameter of 0.3mm; (2) Fe particles are subjected to etching treatment, with 6 hemispherical grooves with a diameter of 0.03mm etched on the surface of the Fe particles;

[0071] Rare earth microparticles: (1) Ce block is made into Ce particles with hollow inside by using 3D printing technology, the outer diameter of the Ce particles is 0.3 mm, and the inner diameter of the Ce particles is 0.029 mm; (2) the Ce particles are heated at high temperature, the heating temperature is controlled to be 790 DEG C, the first heating time is controlled to be 40 min, and the heating number is controlled to be 6 times; (3) the Ce particles are soaked in a carbonic acid solution (the mass ratio of the Ce particles to the carbonic acid solution is 1:30), the temperature of the carbonic acid solution is controlled to be 60 DEG C, and the time is controlled to be 300 h; (4) the Ce particles are taken out from the carbonic acid solution and naturally dried to obtain rare earth microparticles;

[0072] Mn, Si, C, Cr, Ni, rare earth microparticles and Fe are uniformly stirred, the time is controlled to be 50 min, and the stirring speed is controlled to be 30 r / min to obtain a raw material mixture;

[0073] The raw material mixture is melted by using a medium-frequency induction melting furnace, and the mixture is obtained after the raw material is melted and kept for 40 min;

[0074] The mixture is statically placed, cooled, shaped and demolded by using a metal mold to obtain an ingot;

[0075] The ingot is subjected to homogenization treatment, the time is controlled to be 12 h, and the temperature is controlled to be 1200 DEG C;

[0076] The ingot after the above treatment is cut to remove the cap and the outer skin, and is hot forged into a rectangular material with a length of 35 mm and a width of 30 mm and a round bar material with a diameter of 40 mm, and the initial forging temperature in the hot forging is 1050 DEG C, and the final forging temperature is not lower than 900 DEG C;

[0077] The alloy after the above forging is subjected to stress relief annealing treatment, the time is controlled to be 24 h, and the temperature is controlled to be 800 DEG C to obtain a modified rare earth-based memory alloy.

[0078] Comparative Example 1

[0079] A modified rare earth-based memory alloy, the preparation raw materials of the modified rare earth-based memory alloy include: 15 parts of Mn, 5 parts of Si, 0.2 parts of C, 6 parts of Cr, 4 parts of Ni, 0.1 parts of rare earth microparticles, and 69.7 parts of Fe by weight;

[0080] The above-mentioned preparation method of the melting process of the modified rare earth-based memory alloy includes the following steps:

[0081] Mn: (1) Mn block is made into Mn particles by using 3D printing technology, and the diameter of the Mn particles is 0.02 mm; (2) the Mn particles are subjected to etching treatment, and 5 hemispherical grooves with a diameter of 0.002 mm are etched on the surface of the Mn particles;

[0082] Si: (1) Si block is made into Si particles by using 3D printing technology, and the diameter of the Si particles is 0.002 mm; (2) the Si particles are etched, and 5 hemispherical grooves with a diameter of 0.0002 mm are etched on the surface of the Si particles;

[0083] C: (1) C block is made into C particles by using 3D printing technology, and the diameter of the C particles is 0.00002 mm;

[0084] Cr: (1) Cr block is made into Cr particles by using 3D printing technology, and the diameter of the Cr particles is 0.0002 mm; (2) the Mn particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00002 mm are etched on the surface of the Mn particles;

[0085] Ni: (1) Ni block is made into Ni particles by using 3D printing technology, and the diameter of the Ni particles is 0.0002 mm; (2) the Ni particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00002 mm are etched on the surface of the Ni particles;

[0086] Fe: (1) Fe block is made into Fe particles by using 3D printing technology, and the diameter of the Fe particles is 0.2 mm; (2) the Fe particles are etched, and 3-6 hemispherical grooves with a diameter of 0.02 mm are etched on the surface of the Fe particles;

[0087] Rare earth microparticles: (1) the Ce block is heated at high temperature, the heating temperature is controlled to be 695℃, the first heating time is controlled to be 30 min, and the heating number is controlled to be 4 times; (2) the Ce particles are soaked in a carbonic acid solution (the mass ratio of the Ce particles to the carbonic acid solution is 1:30), the temperature of the carbonic acid solution is controlled to be 50℃, and the time is controlled to be 250 h; (3) the Ce particles are taken out from the carbonic acid solution and naturally dried to obtain rare earth microparticles;

[0088] The Mn, Si, C, Cr, Ni, rare earth microparticles and Fe are uniformly stirred, the stirring time is controlled to be 40 min, and the stirring speed is controlled to be 25 r / min to obtain a raw material mixture;

[0089] The raw material mixture is melted by using a medium-frequency induction melting furnace, and after the raw material is melted, the temperature is maintained for 30 min to obtain a mixed liquid;

[0090] The mixed liquid is placed, cooled, formed and demolded by using a metal mold to obtain an ingot;

[0091] The ingot is subjected to homogenization treatment, the time is controlled to be 12 h, and the temperature is controlled to be 1200℃;

[0092] The treated ingot is cut to remove the cap and the outer skin, and is hot forged into a rectangular material with a size of 35mm*30mm and a round bar material with a diameter of 40mm, respectively, wherein the initial forging temperature is 1050 DEG C and the final forging temperature is not lower than 900 DEG C;

[0093] The alloy after forging is subjected to stress relief annealing treatment, the control time is 24h, and the control temperature is 800 DEG C, thereby obtaining the modified rare earth-based memory alloy.

[0094] Comparative Example 2

[0095] A modified rare earth-based memory alloy, wherein the preparation raw materials of the modified rare earth-based memory alloy comprise, by weight: 15 parts of Mn, 5 parts of Si, 0.2 parts of C, 6 parts of Cr, 4 parts of Ni, 0.1 parts of rare earth microparticles, and 69.7 parts of Fe.

[0096] The preparation method of the melting process of the modified rare earth-based memory alloy, comprising the following steps:

[0097] Mn: (1) Mn blocks are made into Mn particles using 3D printing technology, and the diameter of the Mn particles is 0.02mm; (2) the Mn particles are subjected to etching treatment, and 5 hemispherical grooves with a diameter of 0.002mm are etched on the surface of the Mn particles;

[0098] Si: (1) Si blocks are made into Si particles using 3D printing technology, and the diameter of the Si particles is 0.002mm; (2) the Si particles are subjected to etching treatment, and 5 hemispherical grooves with a diameter of 0.0002mm are etched on the surface of the Si particles;

[0099] C: (1) C blocks are made into C particles using 3D printing technology, and the diameter of the C particles is 0.00002mm;

[0100] Cr: (1) Cr blocks are made into Cr particles using 3D printing technology, and the diameter of the Cr particles is 0.0002mm; (2) the Mn particles are subjected to etching treatment, and 3-6 hemispherical grooves with a diameter of 0.00002mm are etched on the surface of the Mn particles;

[0101] Ni: (1) Ni blocks are made into Ni particles using 3D printing technology, and the diameter of the Ni particles is 0.0002mm; (2) the Ni particles are subjected to etching treatment, and 3-6 hemispherical grooves with a diameter of 0.00002mm are etched on the surface of the Ni particles;

[0102] Fe: (1) Fe blocks are made into Fe particles using 3D printing technology, and the diameter of the Fe particles is 0.2mm; (2) the Fe particles are subjected to etching treatment, and 3-6 hemispherical grooves with a diameter of 0.02mm are etched on the surface of the Fe particles;

[0103] Rare earth microparticles: (1) A Ce block is made into a hollow Ce particle using 3D printing technology, the outer diameter of the Ce particle is 0.2 mm, and the inner diameter of the Ce particle is 0.19 mm; (2) The Ce particle is soaked in a carbonic acid solution (the mass ratio of the Ce particle to the carbonic acid solution is 1:30), the temperature of the carbonic acid solution is controlled at 50°C, and the soaking time is controlled at 250 hours; (3) The Ce particle is taken out of the carbonic acid solution and naturally dried to obtain rare earth microparticles;

[0104] The Mn, Si, C, Cr, Ni, rare earth microparticles and Fe are uniformly stirred, the stirring time is controlled at 40 minutes, and the stirring speed is controlled at 25 r / min to obtain a raw material mixture;

[0105] The raw material mixture is melted by a medium-frequency induction melting furnace. When the raw material is melted, the temperature is maintained for 30 minutes to obtain a mixed liquid;

[0106] The mixed liquid is statically placed, cooled, shaped and demolded by a metal mold to obtain an ingot;

[0107] The ingot is subjected to homogenization treatment, the treatment time is controlled at 12 hours, and the temperature is controlled at 1200°C;

[0108] The ingot after the above treatment is cut off the cap and the outer skin, and is hot forged into a rectangular material with a size of 35mmx30mm and a round bar material with a size of Ф40mm, respectively. The initial forging temperature in the hot forging is 1050°C, and the final forging temperature is not lower than 900°C;

[0109] The alloy after the above forging is subjected to stress relief annealing treatment, the treatment time is controlled at 24 hours, and the temperature is controlled at 800°C to obtain a modified rare earth-based memory alloy.

[0110] Comparative Example 3

[0111] A modified rare earth-based memory alloy, the preparation raw materials of the modified rare earth-based memory alloy include, by weight: 15 parts of Mn, 5 parts of Si, 0.2 parts of C, 6 parts of Cr, 4 parts of Ni, 0.1 parts of rare earth microparticles, and 69.7 parts of Fe;

[0112] The above-mentioned preparation method of the melting process of the modified rare earth-based memory alloy includes the following steps:

[0113] Mn: (1) A Mn block is made into a Mn particle using 3D printing technology, and the diameter of the Mn particle is 0.02 mm; (2) The Mn particle is subjected to etching treatment, and 5 hemispherical grooves with a diameter of 0.002 mm are etched on the surface of the Mn particle;

[0114] Si: (1) Si block is made into Si particles by using 3D printing technology, and the diameter of the Si particles is 0.002 mm; (2) the Si particles are etched, and 5 hemispherical grooves with a diameter of 0.0002 mm are etched on the surface of the Si particles;

[0115] C: (1) C block is made into C particles by using 3D printing technology, and the diameter of the C particles is 0.00002 mm;

[0116] Cr: (1) Cr block is made into Cr particles by using 3D printing technology, and the diameter of the Cr particles is 0.0002 mm; (2) the Mn particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00002 mm are etched on the surface of the Mn particles;

[0117] Ni: (1) Ni block is made into Ni particles by using 3D printing technology, and the diameter of the Ni particles is 0.0002 mm; (2) the Ni particles are etched, and 3-6 hemispherical grooves with a diameter of 0.00002 mm are etched on the surface of the Ni particles;

[0118] Fe: (1) Fe block is made into Fe particles by using 3D printing technology, and the diameter of the Fe particles is 0.2 mm; (2) the Fe particles are etched, and 3-6 hemispherical grooves with a diameter of 0.02 mm are etched on the surface of the Fe particles;

[0119] Rare earth microparticles: (1) Ce block is made into hollow Ce particles by using 3D printing technology, and the outer diameter of the Ce particles is 0.2 mm and the inner diameter of the Ce particles is 0.19 mm; (2) the Ce particles are heated at high temperature, the heating temperature is controlled to be 695℃, the first heating time is controlled to be 30 min, and the heating number is controlled to be 4 times; (3) the Ce particles are taken out from the carbonic acid solution and naturally dried to obtain rare earth microparticles;

[0120] The Mn, Si, C, Cr, Ni, rare earth microparticles and Fe are uniformly stirred, the stirring time is controlled to be 40 min, and the stirring speed is controlled to be 25 r / min to obtain a raw material mixture;

[0121] The raw material mixture is melted by using a medium frequency induction melting furnace, and after the raw material is melted, the temperature is kept for 30 min to obtain a mixed liquid;

[0122] The mixed liquid is placed, cooled, formed and demolded by using a metal mold to obtain an ingot;

[0123] The ingot is subjected to homogenization treatment, and the time is controlled to be 12 h and the temperature is controlled to be 1200℃;

[0124] The treated ingot is cut off the cap, cut off the skin, and hot forged into a 35mm*30mm rectangular square material and a Φ40mm round bar material, respectively, and the initial forging temperature in the hot forging is 1050°C, and the final forging temperature is not lower than 900°C.

[0125] The alloy after forging is subjected to stress relief annealing treatment, the control time is 24h, and the control temperature is 800°C, to obtain a modified rare earth-based memory alloy.

[0126] III. Method

[0127] 3.1 According to the implementation standard "GB / T 39985-2021", the hardness of Examples 1-3 is detected, as shown in the following table:

[0128] Item Hardness (MPa) Example 1 800 Example 2 1500 Example 3 1220

[0129] As can be seen from the above table, compared with Example 1, the prepared memory alloy of Example 2 adds rare earth microparticles, which improves the hardness of the memory alloy, and the hardness of the prepared memory alloy of Example 2 is better than that of Example 3, so that the memory alloy has better wear resistance, corrosion resistance and carrying capacity when used.

[0130] 3.2 According to the X-ray fluorescence spectrometry in the implementation standard "GB / T 16597-2019", the distribution of rare earth microparticles in Example 2 and Comparative Examples 1-3 is detected, as shown in the following table:

[0131] Item Distribution Example 2 Uniform Comparative Example 1 Non-uniform Comparative Example 2 Non-uniform Comparative Example 3 Non-uniform

[0132] As can be seen from the above table, compared with Comparative Examples 1-3, the Ce in the prepared memory alloy of Example 2 is more uniformly distributed, by relatively increasing the volume of Ce particles, the hardness after Ce quenching and the frictional resistance after soft acid corrosion of the surface, so that the Ce particles are mixed more uniformly when mixed with other raw materials, therefore, the internal Ce distribution is more uniform when the memory alloy is forged, thereby avoiding the segregation of Ce composition in the memory alloy as much as possible, which helps to ensure the overall performance of the memory alloy.

[0133] 3.3 DYNAPEN test experiment

[0134] Experimental steps: the modified rare earth-based memory alloy prepared from Example 2 and Comparative Examples 1-3 is used to draw a straight line on the modified rare earth-based memory alloy with a 36# dynapen, and then the surface marking state of the four modified rare earth-based memory alloys is recorded, as shown in the following table:

[0135] Item State Example 2 Presented in an uninterrupted straight line, and the color was uniform Comparative Example 1 Presented in a broken line, and the color was non-uniform Comparative Example 2 Presented in a broken line, and the color was uniform Comparative Example 3 Presented in a broken point, and the color was non-uniform

[0136] From the above table, it can be seen that the dyne pen is more likely to stay on the surface of the modified rare earth-based shape memory alloy in Example 2 compared with Comparative Examples 1-3, so it is known that the modified rare earth-based shape memory alloy has good wettability, and thus is more likely to form a uniform coating or printing effect on the outside of the modified rare earth-based shape memory alloy.

[0137] The above-described examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which are within the scope of protection of the present application.

Claims

1. A shape memory alloy based on modified rare earth elements, characterized in that, The raw materials for preparing the modified rare earth-based shape memory alloy, by weight, include: 15 parts Mn, 5 parts Si, 0.15-0.25 parts C, 3-9 parts Cr, 2-6 parts Ni, 0-0.2 parts rare earth particles, and 64.55-74.85 parts Fe.

2. The shape memory alloy based on modified rare earth elements according to claim 1, characterized in that, The specific preparation method of Mn is as follows: (i) Mn blocks are made into Mn particles using 3D printing technology, and the diameter of the Mn particles is 0.01-0.03mm; (ii) The Mn particles are etched to form 3-6 hemispherical grooves with a diameter of 0.001-0.003mm on the surface of the Mn particles. The specific preparation method of Si is as follows: (i) Si blocks are made into Si particles using 3D printing technology, and the diameter of the Si particles is 0.001-0.003mm; (ii) The Si particles are etched to form 3-6 hemispherical grooves with a diameter of 0.0001-0.0003mm on the surface of the Si particles. The specific preparation method of C is as follows: (i) the C block is made into C particles using 3D printing technology, and the diameter of the C particles is 0.00001-0.00003mm; The specific preparation method of Cr is as follows: (i) Cr blocks are made into Cr particles using 3D printing technology, and the diameter of the Cr particles is 0.0001-0.0003mm; (ii) Mn particles are etched to form 3-6 hemispherical grooves with a diameter of 0.00001-0.00003mm on the surface of the Mn particles. The specific preparation method of Ni is as follows: (i) Ni blocks are made into Ni particles using 3D printing technology, and the diameter of the Ni particles is 0.0001-0.0003mm; (ii) The Ni particles are etched to form 3-6 hemispherical grooves with a diameter of 0.00001-0.00003mm on the surface of the Ni particles. The specific preparation method of Fe is as follows: (i) Fe blocks are made into Fe particles using 3D printing technology, and the diameter of the Fe particles is 0.1-0.3 mm; (ii) The Fe particles are etched to form 3-6 hemispherical grooves with a diameter of 0.01-0.03 mm on the surface of the Fe particles.

3. The shape memory alloy based on modified rare earth elements according to claim 1, characterized in that, The specific preparation method of the rare earth microparticles is as follows: (i) Ce blocks are made into hollow Ce particles using 3D printing technology. The outer diameter of the Ce particles is 0.1-0.3 mm, and the inner diameter of the Ce particles is 0.09 mm-0.29 mm; (ii) The Ce particles are then heated at high temperature, with the heating temperature controlled at 600-790℃, the heating time controlled at 20-40 min, and the heating times controlled at 1-6 times; (iii) The Ce particles are immersed in a weak acid solution, with the temperature of the weak acid solution controlled at 40-60℃, and the time controlled at 200-300 h; (iv) The Ce particles are taken out of the weak acid solution and air-dried naturally to obtain rare earth microparticles.

4. A shape memory alloy based on modified rare earth elements according to claim 3, characterized in that, The mass ratio of Ce particles to the weak acid solution is 1:

30.

5. A shape memory alloy based on modified rare earth elements according to claim 3, characterized in that, The weak acid solution is either acetic acid or carbonic acid.

6. A method for preparing a shape memory alloy based on modified rare earth elements according to any one of claims 1-5, characterized in that, Includes the following steps: S1, Mn, Si, C, Cr, Ni, rare earth particles and Fe are stirred uniformly for 30-50 min and the stirring speed is controlled at 20-30 r / min to obtain a raw material mixture; S2, a medium-frequency induction melting furnace is used to melt the raw material mixture. During melting, after the raw materials are melted, the mixture is kept at the temperature for 20-40 minutes to obtain the mixed liquid. S3, the mixture is allowed to stand, cool, form, and demold using a metal mold to obtain an ingot; S4. Homogenize the ingot for 12 hours at a temperature of 1200℃. S5, the cap and outer skin of the ingot after S4 treatment are cut off, and it is hot forged into rectangular squares of 35mm×30mm and round bars of Ф40mm respectively. The initial forging temperature during hot forging is 1050℃, and the final forging temperature is not lower than 900℃. S6, the alloy after S5 forging is subjected to stress-relief annealing treatment, with a controlled time of 24 hours and a controlled temperature of 800℃, to obtain a shape memory alloy based on modified rare earth.