WO2002014565A1 - Ferromagnetic shape-memory alloy - Google Patents

Abstract

A ferromagnetic shape-memory alloy which has a composition consisting of 5 to 70 at.% cobalt, 5 to 70 at.% nickel, 5 to 50 at.% aluminum, and unavoidable impurities as the remainder and has either a single-phase structure consisting of a ß phase of a B2 structure or a two-phase structure consisting of a η phase of an fcc structure and a ß phase of a B2 structure; or a ferromagnetic shape-memory alloy which has a composition consisting of 35 to 65 at.% cobalt, 20 to 35 at.% gallium, and nickel and unavoidable impurities as the remainder and has either a single-phase structure consisting of a ß phase of a B2 structure or a two-phase structure consisting of a ß phase of a B2 structure and an fcc structure as a second phase.

Description

 Specification

Ferromagnetic shape memory alloy

Technical field

 The present invention relates to a ferromagnetic shape memory alloy having excellent ductility, having ferromagnetism, and causing martensite transformation.

Background art

 Among the components that make up a mechanical structure, functional components that generate deformation, movement, or stress are called factories. Actuator materials include piezoelectric materials, magnetostrictive materials, electrorheological fluids, and shape memory alloys. In all of the materials, the function of the actuator is manifested by a phase transformation phenomenon of the crystal structure, which involves the conversion of physicochemical properties and mechanical energy.

 Among the materials used for actuators, shape memory alloys utilize a martensitic transformation by cooling and a reverse transformation mechanism by heating. In other words, the shape is constrained in the alloy by constraining the shape in the austenite state, which is the high-temperature phase, and the alloy is memorized by heat treatment. After being transformed in the martensite state, which is the low-temperature phase, the reverse transformation that returns to austenite when heated And return to the original shape.

Generally, the transformation temperature during heating is higher than the transformation temperature during cooling, and the temperature difference is called temperature hysteresis. The case where the temperature hysteresis is small is called thermoelastic martensite transformation, and a large shape recovery strain of about 5% can be obtained. However, shape memory alloys utilizing thermoelastic martensitic transformation require heating and cooling because they exhibit a shape memory effect due to temperature changes.However, the cooling process is rate-limited by heat dissipation, so shape memory The response speed of the effect is slow. Therefore, the shape memory effect is repeatedly There was a problem that it was difficult to use it every night.

 Therefore, in recent years, ferromagnetic shape memory alloys have attracted attention as a new factor material. Ferromagnetic shape memory alloys are intended to enhance the response of the shape memory effect by applying magnetic energy externally, not by temperature change, to induce magnetically induced martensite transformation. Alternatively, when a magnetic field is applied in the martensitic phase, distortion occurs due to twin movement. This distortion is intended to be applied as an actuary.

 Japanese Patent Application Laid-Open No. 11-269611 discloses an iron-based magnetic shape memory alloy and a method for producing the same. This technology applies magnetic energy to iron-based magnetic shape memory alloys based on Fe-Pd-based alloys with a Pd content of 27-32 at.% Or Fe-Pt-based alloys with a Pt content of 23-30 at. The purpose of the present invention is to provide a shape-memory phenomenon by imparting a magnetically induced martensitic transformation. However, with this technology, it was difficult to give a complex and precise shape as a mechanical part because of the low ductility of the material, and it was economically disadvantageous because of the high raw material price.

 JP-A-5-311287 discloses a ferromagnetic Cu-based shape memory material and a method for producing the same. In this technology, a Cu—A1-Mn alloy powder is pressed, solidified, molded, sintered, and processed to use the shape memory phenomenon in an electrical switching device and a temperature sensing sensor. However, with this technology, it was difficult to impart a complex and precise shape as a mechanical part because the powder material was pressed and sintered and then processed.

U.S. Pat. No. 5,958,154 discloses a technique in which a magnetic field is applied to a material for an actuator of a Ni-Mn-Ga alloy to exhibit a shape memory phenomenon. However, this technique has a problem that it is difficult to give a complicated and precise shape as a mechanical part because the ductility of the material is low, and the repetition characteristics are poor. Disclosure of the invention

 An object of the present invention is to solve the above problems and provide a ferromagnetic shape memory alloy having excellent ductility, having ferromagnetism, and causing martensitic transformation. In order to achieve this object, the present invention provides a ferromagnetic material containing Co as a component and having a single-phase structure composed of a / 3 phase having a B 2 structure or a two-phase structure composed of eight phases and another phase. Shape memory alloy.

 That is, the present invention provides a composition comprising 5 to 70 atomic% of Co, 5 to 70 atomic% of Ni, and 5 to 50 atomic% of A1, with the balance being unavoidable impurities and a single phase comprising a B 2 structure ^ phase. It is a ferromagnetic shape memory alloy having a phase structure or a two-phase structure composed of 7 phases and a β phase having a B 2 structure.

 Further, the present invention provides a composition containing 35 to 65 atomic% of Co and 20 to 35 atomic% of Ga, with the balance being Ni and unavoidable impurities, and a single-phase structure or a B 2 structure composed of a ^ phase having a B 2 structure. This is a ferromagnetic shape memory alloy having a three-phase structure and a two-phase structure composed of a second phase having a cccc structure.

In a preferred embodiment of the present invention, in addition to the above-mentioned composition, it is preferable to contain 0.001 to 30 atomic% of Fe and / or 0.001 to 30 atomic% of Mn. In addition to the above-described composition, it is preferable that one of Ga, In, and Si is contained in an amount of 0.001 to 50 atomic%, or a total of two or more of them is contained in an amount of 0.001 to 50 atomic%. In addition to the above-described composition, it is preferable that one of In and Si is contained at 0.001 to 50 atomic%, or two of them are contained at 0.001 to 50 atomic% in total. In addition to the above-mentioned composition, B is 0.0005 to 0.01 atomic%, Mg is 0.0005 to 0.01 atomic%, C is 0.0005 to 0.01 atomic%, and 0.0005 is 0.0005 atomic%. It is preferable to contain one or more of 0.01 to 0.01 atomic%. In addition to the above-described composition, one of Pt, Pd, Au, Ag, Nb, V, Ti, Cr, Zr, Cu, W, and Mo is 0.001 to 10 atomic% or two or more. The total content is preferably 0.001 to 10 atomic%. Further, when the present invention has a single-phase structure, as a preferred embodiment, it is preferable that the ^ phase having the B2 structure is a single crystal.

When the present invention has a two-phase structure, as a preferred embodiment, the volume fraction of the seven phases is 0.0 :! It is preferable to satisfy the range of ~ 80% by volume. Or the second phase of the above-described fee structure, epsilon of § phase and / or L 1 ₂ structure 7 'phase contact and Z or hcp structure of A 1 structures - is preferably C ₀ phase, the I cc It is preferable that the volume fraction of the second phase of the structure satisfies the range of 0.01 to 80% by volume. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a perspective view showing the orientation of the test piece and the direction of the magnetic field.

 Description of symbols>

 1 Test piece

2 best mode for carrying out the invention

 The present invention is a ferromagnetic shape memory alloy containing Co as a component and having a single-phase structure composed of a B 2 structure ^ phase or a two-phase structure composed of an S phase and another phase.

First, the composition of the ferromagnetic shape memory alloy containing 5 to 70 atomic% of Co according to the present invention will be described. The ferromagnetic shape memory alloy of the present invention contains 5 to 70 atomic% of Co, 5 to 70 atomic% of Ni, and 5 to 50 atomic% of A1, with the balance being unavoidable impurities. Furthermore, Fe is 0.0101-30 atomic%, Mn is 0.001-30 atomic%, Ga is 0.001-50 atomic%, In is 0.001-50 atomic%, Si is 0.001-50 atomic%, B is 0.0005-0.01 atomic%, It is preferable to contain 0.0005 to 0.01 atomic% of Mg, 0.0005 to 0.01 atomic% of C, and 0.0005 to 0.01 atomic% of P. Further, one of Pt, Pd, Au, Ag, Nb, V, Ti, Cr, Zr, Cu, W and Mo is 0.001 to: L0 atomic% or a total of two or more is 0.00 :! ~ 10 atomic% is preferred New

 Co is an element that improves shape memory characteristics and magnetic characteristics together with Ni and Al. However, if the Co content is less than 5 atomic%, the ferromagnetism disappears. If the Co content exceeds 70 atomic%, no shape memory effect is exhibited. Therefore, the Co content needs to satisfy the range of 5 to 70 atomic%.

 Ni is an element that improves shape memory characteristics together with Co and A1. However, when the Ni content is less than 5 atomic% or the Ni content exceeds 70 atomic%, the shape memory effect is not exhibited. Therefore, the Ni content must satisfy the range of 5 to 70 atomic%.

A1 is an element that improves shape memory characteristics and magnetic characteristics together with Co and Ni. However, when the A1 content is less than 5 atomic% or the A1 content exceeds 50 atomic%, the shape memory effect is not exhibited. Thus, A1 content Ru required force ^s ¾ satisfying the range of 5 to 50 atomic%>.

 Fe is an element that expands the region where the / 2 phase of the B 2 structure (the so-called CeCl structure) exists, and the temperature at which the base structure mainly composed of the ^ phase of the B 2 structure causes martensitic transformation (hereinafter, martensitic transformation). It is an element that changes the temperature at which the magnetic properties change from paramagnetic to ferromagnetic (hereinafter referred to as the Curie temperature). However, if the Fe content is less than 0.001 at%, the effect of expanding the region where the three phases of the B 2 structure exist cannot be exhibited. On the other hand, if the Fe content exceeds 30 atomic%, the effect of expanding the existence region of the / 3 phase of the B 2 structure is saturated. Therefore, the Fe content preferably satisfies the range of 0.001 to 30 atomic%.

Mn is an element that promotes the formation of the / 3 phase of the B 2 structure and an element that changes the martensitic transformation temperature and the Curie temperature. However, if the Mn content is less than 0.001 atomic%, the effect of expanding the region where the / 3 phase of the B2 structure is present is not exhibited. Further, _c thus the Mn content is effective to widen the existing area of more than 30 atomic% B 2 structure / 3-phase saturated, Mn content is preferably within the ranges of 0.001 to 30 atomic% . Ga, together with In and Si, is an element that changes the martensite transformation temperature and the Curie temperature.The synergistic effect of In and Si reduces the martensite transformation temperature and the curry temperature within the range of -200 to 200 ° C. Can be controlled freely. However, if the Ga content is less than 0.001 atomic%, the effects of controlling the martensite transformation temperature and the Curie temperature are not exhibited. Further, even if the Ga content exceeds 50 atomic%, the effects of controlling the martensite transformation temperature and the Curie temperature are not exhibited. Therefore, the Ga content preferably satisfies the range of 0.001 to 50 atomic%.

In, along with Ga and Si, an element that changes the martensitic transformation temperature and the Curie temperature, by the synergistic effect of the Ga and Si, freely martensitic transformation temperature and the Curie temperature in the range of one 200 to 200 ^D C Can be controlled. However, when the In content is less than 0.001 atomic%, the effects of controlling the martensitic transformation temperature and the Curie temperature are not exhibited. Further, even if the In content exceeds 50 atomic%, the effect of controlling the martensite transformation temperature and the Curie temperature is not exhibited. Therefore, the In content preferably satisfies the range of 0.001 to 50 atomic%.

 Si, together with Ga and In, is an element that changes the martensite transformation temperature and the Curie temperature.The synergistic effect of Ga and In allows the martensite transformation temperature and the Curie temperature to be adjusted within the range of 200 to 200 ° C. Can be controlled. When the Si content is less than 0.001 atomic%, the effects of controlling the martensitic transformation temperature and the Curie temperature are not exhibited. Further, even if the Si content exceeds 50 atomic%, the control effects of the martensite transformation temperature and the Curie temperature are not exhibited. Therefore, the Si content preferably satisfies the range of 0.001 to 50 atomic%.

B, together with Mg, C and P, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, when the B content is less than 0.0005 atomic%, the effects of making the structure finer and improving the ductility of the material are not exhibited. On the other hand, if the B content exceeds 0.01 atomic%, the effect of miniaturization and improvement of ductility saturates. Therefore, the B content is 0.00 It is preferable to satisfy the range of 05 to 01 atomic%.

 Mg, together with B, C and P, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, when the Mg content is less than 0.0005 atomic%, the effects of making the structure finer and improving the ductility are not exhibited. If the Mg content exceeds 0.01 atomic%, the effects of miniaturization and improvement of ductility are saturated. Therefore, the Mg content preferably satisfies the range of 0.0005 to 0.01 atomic%.

 C, together with B, Mg and P, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, if the C content is less than 0.0005 atomic%, the effects of miniaturizing the structure and improving the ductility of the material are not exhibited. If the C content exceeds 0.01 atomic%, the effects of miniaturization and improvement of ductility are saturated. Therefore, the C content preferably satisfies the range of 0.0005 to 0.01 atomic%.

 P, together with B, Mg and C, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, if the P content is less than 0.0005 atomic%, the effects of miniaturizing the structure and improving the ductility of the material are not exhibited. If the P content exceeds 0.01 atomic%, the effects of miniaturization and improvement of ductility are saturated. Therefore, the P content preferably satisfies the range of 0.0005 to 0.01 atomic%.

 All of Pt, Pd, Au, Ag, Nb, V, Ti, Cr, Zr, Cu, W and Mo not only change the martensitic transformation temperature and Curie temperature, but also refine the structure and improve the ductility of the material. It is an element to improve. However, if these elements are less than 0.001 at%, the effects of making the structure finer and improving the ductility of the material are not exhibited. If these elements exceed 10 atomic%, the effect of miniaturization and improvement of ductility saturates. Therefore, when one of these elements is added, its content satisfies the range of 0.001 to 10 atomic%, and when two or more of these elements are added, the total content is 0.001 to; It is preferable to satisfy the range of L0 atomic%.

Next, regarding the structure of the ferromagnetic shape memory alloy containing 5 to 70 atomic% of Co according to the present invention, explain. The ferromagnetic shape memory alloy of the present invention has a force having a single phase structure composed of a β phase of B 2 structure (so-called CeCl structure), or a two phase structure composed of 7 phases of ί cc structure and β phase of Β 2 structure. Having.

 When it has a single phase structure, it may be a single crystal or a polycrystal. However, single crystals are preferred because of their excellent shape memory properties and magnetic properties. In the present invention, a method for obtaining a single crystal is not limited to a specific method, and a conventionally known method such as a Chiyoklarski method may be used.

 The two-phase structure is more preferable because the ductility, shape memory properties and magnetic properties are remarkably improved as compared with the single-phase structure. However, if the volume fraction of the seven phases is less than 0.01% by volume, the effect of improving shape memory characteristics and magnetic characteristics is not exhibited. On the other hand, when the volume fraction of the y-phase exceeds 80% by volume, the effect of improving shape memory properties and magnetic properties is saturated. Therefore, the volume fraction of the y phase preferably satisfies the range of 0.01 to 80% by volume.

When producing the ferromagnetic shape memory alloy of the present invention, the molten metal is solidified, heat-treated at 500 to L400 ⁶ C, and then quenched. In this way, a two-phase structure of a phase and a seven phase is obtained, and then, when processed into a predetermined shape, excellent ductility is exhibited.

 After quenching, the sheet material is further subjected to cold rolling or hot rolling to form a sheet material, processed into a predetermined shape, and subjected to a recrystallization heat treatment at 500 to 1400 ° C., thereby imparting a shape memory function to B 2. A ferromagnetic shape memory alloy with a single-phase structure consisting of the ^ phase is obtained.

 This single-phase ferromagnetic shape memory alloy is further heat-treated at 500 to 1400 ° C to preferentially precipitate seven phases at the / 3 phase grain boundary, thereby providing B2 with a shape memory function. A ferromagnetic shape memory alloy with a two-phase structure consisting of a ^ phase with a structure and seven phases with a ί cc structure with excellent ductility is obtained.

Next, the composition of the ferromagnetic shape memory alloy containing 35 to 65 atomic% of Co according to the present invention will be described. explain. The ferromagnetic shape memory alloy of the present invention contains 35 Co65 atomic% of Co and 20-35 atomic% of Ga, with the balance being Ni and unavoidable impurities. Furthermore, 0.001 to 30 atomic% of Fe, 0.001 to 30 atomic% of Mn, 0.001 to 50 atomic% of In, 0.001 to 50 atomic% of Si, and 0.0005 to 0.01 of B Atomic%, 0.0005 to 0.01 atomic% of Mg, 0.0005 to 0.01 atomic of C, and 0.0005 to 0.01 atomic% of P are preferable. In addition, one of Pt, Pd, Au, Ag, Nb, V, Ti, Cr, Zr, Cu, W and Mo is 0.001 ~; L0 atomic% or two or more is 0.001 ~ 10 It is preferable to contain the atom%.

 Co is an element that improves shape memory characteristics and magnetic characteristics together with Ni. However, if the Co content is less than 35 atomic%, the ferromagnetism disappears. If the Co content exceeds 65 atomic%, no shape memory effect is exhibited. Therefore, the Co content must satisfy the range of 35 to 65 atomic%.

 Ga is an element that changes the martensite transformation temperature and the Curie temperature, and can freely control the martensite transformation temperature and the Curie temperature in the range of -200 to 200 ° C. However, if the Ga content is less than 20 atomic%, the effects of controlling the martensite transformation temperature and the Curie temperature are not exhibited. Further, even if the Ga content exceeds 35 atomic%, the effects of controlling the martensite transformation temperature and the Curie temperature are not exhibited. Therefore, the Ga content must satisfy the range of 20 to 35 atomic%.

 Is an element that improves shape memory characteristics together with Co, and the shape memory effect is not exhibited if the Ni content is insufficient or excessive. Therefore, the balance of Co and Ga contained within the above range must be Ni.

Fe is an element that expands the existence region of the / 3 phase of the B 2 structure (so-called CeCl structure). It is an element that changes the temperature at which the magnetic properties change from paramagnetic to ferromagnetic (hereinafter referred to as the Curie temperature). When the Fe content is less than 0.001 atomic%, the effect of expanding the region where the B 2 structure phase exists is exhibited. Absent. On the other hand, if the Fe content exceeds 30 atomic%, the effect of expanding the region where the ^ phase having the B 2 structure exists is saturated. Therefore, the Fe content preferably satisfies the range of 0.001 to 30 atomic%.

Mn is an element that promotes the formation of the / 3 phase of the B 2 structure and an element that changes the martensite transformation temperature and the Curie temperature. However, if the Mn content is less than 0.001 atomic%, the effect of expanding the region where the / 3 phase of the B2 structure is present is not exhibited. Further, _c effect of widening the existing area of ^ phases of B 2 structure when the Mn content exceeds 30 atomic% is saturated Therefore, Mn content is preferably within the ranges of 0.001 to 30 atomic%.

 In is an element that changes the martensite transformation temperature and the Curie temperature together with Si, and the synergistic effect with Si can freely control the martensite transformation temperature and the Curie temperature in the range of -200 to 200 ° C. However, when the In content is less than 0.001 atomic%, the effects of controlling the martensite transformation temperature and the Curie temperature are not exhibited. Further, even if the In content exceeds 50 atomic%, the effect of controlling the martensitic transformation temperature and the Curie temperature is not exhibited. Therefore, the In content preferably satisfies the range of 0.001 to 50 atomic%.

 Si, together with In, is an element that changes the martensite transformation temperature and Curie temperature, and the synergistic effect with In allows the martensite transformation temperature and Curie temperature to be freely controlled in the range of -200 to 200 ° C. However, when the Si content is less than 0.001 atomic%, the control effects of the martensite transformation temperature and the Curie temperature are not exhibited. Further, even if the Si content exceeds 50 atomic%, the effect of controlling the martensitic transformation temperature and the Curie temperature is not exhibited. Therefore, the Si content preferably satisfies the range of 0.001 to 50 atomic%.

B, together with Mg, C and P, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, when the B content is less than 0.0005 atomic%, the effects of making the structure finer and improving the ductility of the material are not exhibited. The B content is 0.01 atomic%. If it exceeds, the effects of miniaturization and improvement of ductility are saturated. Therefore, the B content preferably satisfies the range of 0.0005 to 0.01 atomic%.

 Mg, together with B, C and P, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, if the content is less than 0.0005 atomic%, the effect of making the structure finer and improving the ductility is not exhibited. If the Mg content exceeds 0.01 atomic%, the effects of miniaturization and improvement of ductility are saturated. Therefore, the Mg content preferably satisfies the range of 0.0005 to 0.01 atomic%.

 C, together with B, Mg and P, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, if the C content is less than 0.0005 atomic%, the effects of miniaturizing the structure and improving the ductility of the material are not exhibited. If the C content exceeds 0.01 atomic%, the effects of miniaturization and improvement of ductility are saturated. Therefore, the C content preferably satisfies the range of 0.0005 to 0.01 atomic%.

 P, together with B, Mg and C, is an element that refines the structure and improves the ductility and shape memory properties of the material. However, if the P content is less than 0.0005 atomic%, the effects of miniaturizing the structure and improving the ductility of the material are not exhibited. If the P content exceeds 0.01 atomic%, the effects of miniaturization and improvement of ductility are saturated. Therefore, the P content preferably satisfies the range of 0.0005 to 0.01 atomic%.

All of Pt, Pd, Au, Ag, Nb, V, Ti, Cr, Zr, Cu, W and Mo not only change the martensite transformation temperature and Curie temperature, but also refine the structure and ductility of the material. Is an element that improves the However, if these elements are less than 0.001 at%, the effects of making the structure finer and improving the ductility of the material are not exhibited. If these elements exceed 10 atomic%, the effect of miniaturization and improvement of ductility saturates. Therefore, when one of these elements is added, the content satisfies the range of 0.001 to 10 atomic%, and when two or more of these elements are added, the total content is 0.001 to: It is preferable to satisfy the range of L0 atomic%. Next, the structure of the ferromagnetic shape memory alloy containing 35 to 65 atomic% of Co according to the present invention will be described. The ferromagnetic shape memory alloy of the present invention has a single phase structure composed of a β phase having a B 2 structure (so-called CeCl structure) or a two phase structure composed of a ^ phase having a Β 2 structure and a second phase having an fcc structure. Having.

 When it has a single phase structure, it may be a single crystal or a polycrystal. However, single crystals are preferred because of their excellent shape memory properties and magnetic properties. In the present invention, a method for obtaining a single crystal is not limited to a specific method, and a conventionally known method such as a Chiyoklarski method may be used.

The two-phase structure is more preferable because the ductility, shape memory properties and magnetic properties are remarkably improved as compared with the single-phase structure. The second phase of the dual phase structure is of A 1 structure § phase and / or L 1 ₂ Structure of § 'phase and or hcp structure having an fcc structure epsilon - C. It is preferably a phase. However, if the volume fraction of the second phase is less than 0.01% by volume, the effect of improving shape memory properties and magnetic properties is not exhibited. On the other hand, when the volume fraction of the second phase exceeds 80% by volume, the effect of improving shape memory properties and magnetic properties is saturated. Therefore, the volume fraction of the second phase preferably satisfies the range of 0.01 to 80% by volume.

 When producing the ferromagnetic shape memory alloy of the present invention, the molten metal is solidified, heat-treated at 500 to 1400 ° C., and then quenched. In this way, a two-phase structure of the phase and the second phase (ie, the α phase and the Z or 7 ′ phase) is obtained, and then, when processed into a predetermined shape, it exhibits excellent ductility.

 After quenching, the sheet material is further subjected to cold rolling or hot rolling to form a sheet material, processed into a predetermined shape, and subjected to a recrystallization heat treatment at 500 to 1400 ° C., thereby imparting a shape memory function to B 2. A ferromagnetic shape memory alloy with a single-phase structure consisting of the ^ phase is obtained.

This ferromagnetic shape memory alloy having a single phase structure is further heat-treated at 300 to 1400 ° C, and the 7 phase and / or the 7 phase and the Z or ε — (:. Analysis The ferromagnetic shape of a two-phase structure consisting of a B2 structure / 3 phase with shape memory function and a fee structure second phase (ie, 7 phase and / or 7 'phase) with excellent ductility A memory alloy is obtained.

 Example>

 (Example 1)

 After smelting the alloys of the components shown in Table 1, solidifying them, performing heat treatment at 500 to 1400 ° C, further quenching and cold rolling, cutting out a sheet of predetermined size, At 1400, a recrystallization heat treatment was performed to produce a polycrystalline phase (B2 structure) ferromagnetic shape memory alloy having a shape memory function. This is referred to as Invention Example 1 and Invention ¾.

 Inventive Examples 3 and 4 show that the polycrystalline ^ phase was formed in the same manner as in Inventive Examples 1 and 2, and then the single crystal ^ phase (B 2 structure) was strengthened by strain annealing. This is an example of manufacturing a magnetic shape memory alloy.

 Inventive Example 5 and Inventive Example 6 were obtained by forming a polycrystalline phase in the same manner as in Inventive Example 1 and Inventive Example 2, and then heat-treating at 500 to 1350 ° C to bring the yS phase grain boundary to r. In this example, a phase is precipitated to produce a ferromagnetic shape memory alloy having a two-phase structure of 8 phases having a B2 structure having a shape memory function and 7 phases having a 延 cc structure having excellent ductility. The volume fraction of the 7 phase of Invention Example 5 was 10% by volume, and the volume fraction of the Ί phase of Invention Example 6 was 40% by volume. Comparative Example 1 is an example in which the content of Co is out of the range of the present invention, Comparative Example 2 is an example in which the content of Ni is out of the range of the present invention, and Comparative Example 3 is an example in which the content of A1 is in the range of the present invention. This is an example that is out of range. In Comparative Example 1, a polycrystal; S phase was produced in the same manner as in Inventive Examples 1 and 2. In Comparative Example 2, a single-crystal phase was produced in the same manner as in Inventive Examples 3 and 4. In Comparative Example 3, a two-phase structure consisting of seven phases was formed in the same manner as in Inventive Examples 5 and 6. The volume fraction of the seven phases in Comparative Example 3 was 90% by volume.

Investigation of shape memory characteristics and magnetostriction characteristics of Invention Examples 1 to 6 and Comparative Examples 1 to 3 did. The cold rolling reduction was also investigated. The results are shown in Table 2. For the shape memory characteristics, a strip of 50 mm x 5 mm x 0.3 mm was cut out and subjected to a bending test to measure the recovery rate when a 5% bending strain was applied.

 The magnetostriction characteristics of Invention Examples 3 to 4 and Comparative Example 2, which are a single crystal ^ phase, were cut out from a test piece with dimensions of 5ππηΧ5 The strain gauge 2 was mounted, and a magnetic field H having a strength of 30 AZm was applied in the [001] direction to measure the amount of strain. In Invention Examples 5, 6 and Comparative Example 3, which have a two-phase structure of / 3 phase and 7 phase, a magnetic field was applied in a direction parallel to the rolling direction using a 30 mm X 10 mm X 1 band-shaped test piece. The amount of strain in the rolling direction at that time was measured.

 The recovery rate (%) of the shape memory property is a value calculated by the following equation (1), and the magnetostrictive property (%) is a value calculated by the following equation (2). %) Is a value calculated by the following equation (3).

 Recovery rate of shape memory characteristics (%)

= 100X {(ε _d -ε r) / ε _d } · · · (1) ε _d : surface distortion after deformation

ε _r : Surface distortion when recovered

Magnetostrictive property (%) = 100 X {(L ₂ -Li) / Li} · · · (2)

Li: Length before applying magnetic field (mm)

L ₂ : Length after applying magnetic field (mm)

 Cold rolling rate (%) = 100 X {(t 1-2) / t 1} · · · (3) t i: thickness before cold rolling (mm)

t ₂ : Thickness after cold rolling (mm)

As is evident from Table 2, when the invention examples 1 to 6 are compared with the comparative examples 1 to 3, the invention example shows that the shape memory alloy which is excellent in the recovery rate of the shape memory property, the magnetostriction property, and the cold rolling rate is better. I got it. Among the invention examples 1 to 6, the single-phase structure of a single crystal ^ phase (invention example By forming a two-phase structure (3, 4) or a / 3 phase and a 7-phase (Invention Examples 5 and 6), compared with a polycrystalline / 3-phase single-phase structure (Invention Examples 1 and 2), A ferromagnetic shape memory alloy with more excellent recovery rate of yield memory property, magnetostriction property and cold rolling rate was obtained.

 In addition, as shown in Invention Example 6 which is particularly excellent in processing performance (that is, high in cold rolling ratio) and Invention Example 5 which is excellent in recovery rate of shape memory characteristics and magnetostriction characteristics, the type and amount of additive elements are appropriate. It is possible to obtain a ferromagnetic shape memory alloy having the performance according to the purpose and application by selecting the above.

 (Example 2)

 After smelting the alloys of the components shown in Table 3, they were solidified, heat-treated at 500 to 1400 ° C in the same manner as in Example 1, further quenched and cold-rolled, and then cooled to a predetermined size. The sheet material was cut out and subjected to a recrystallization heat treatment at 500 to 1400 ° C to produce a polycrystalline ^ phase (B2 structure) ferromagnetic shape memory alloy with a shape memory function. These are referred to as Invention Example 7 and Invention Example 8.

 Inventive Examples 9 and 10 are obtained by forming a polycrystalline / 3 phase in the same manner as in Inventive Examples 7 and 8, and then subjecting the single-crystal ^ phase (B 2 structure) to strain annealing. This is an example of manufacturing a ferromagnetic shape memory alloy.

 Inventive Examples 11 and 12 are similar to Inventive Examples 7 and 8 except that a polycrystalline ^ phase was generated in the same manner as in Inventive Examples 7 and 8, and then heat-treated at 500 to 1350 ° C to generate a ^ phase crystal boundary. Precipitated 7 phase and Z or 7 'phase, B2 structure / 3 phase with shape memory function and 2nd phase of 第 cc structure with excellent ductility (ie 7 phase and Ζ or 7' phase) This is an example of manufacturing a two-phase ferromagnetic shape memory alloy. The volume fraction of the second phase of Invention Example 11 was 10% by volume, and the volume fraction of the second phase of Invention Example 12 was 40% by volume.

Comparative Example 4 is an example in which the content of Co is out of the range of the present invention, and Comparative Example 5 is an example in which the content of Ga is out of the range of the present invention. In Comparative Example 4, a polycrystalline j8 phase was produced in the same manner as in Inventive Examples 7 and 8. Comparative Example 5 was performed in the same manner as in Invention Examples 11 and 12. In this way, a two-phase structure of a third phase and a second phase was formed. The volume fraction of the second phase in Comparative Example 5 was 90% by volume.

 Shape memory characteristics and magnetostriction characteristics of Inventive Examples 7 to 12 and Comparative Examples 4 to 5 were investigated. The cold rolling reduction was also investigated. The results are shown in Table 4.

 For shape memory characteristics, a strip of 50 mm x 5 thigh x 0.3 mm was cut out and subjected to a bending test to measure the recovery rate when 2% bending strain was applied.

 Magnetostrictive characteristics are as follows: Invention Example 9-: single crystal /? Phase: For L0 and Comparative Example 5, as shown in FIG. 1, a test piece having a size of 5 mm × 5 bandages × 5 mm was cut out, and the (1 10) plane A strain gauge 2 was attached to the sample, and a magnetic field H having a strength of 30 A / m was applied in the [001] direction to measure the amount of strain. In Invention Examples 11, 12 and Comparative Example 5, which have a two-phase structure of the / 3 phase and the second phase (that is, the 7 phase and / or 7 'phase), a 30 minxl0minx lmm strip-shaped specimen was used in the rolling direction. The amount of strain in the rolling direction when a magnetic field was applied in a parallel direction was measured.

 The recovery rate (%) of the shape memory characteristic is a value calculated by the following equation (1), as in Table 2, and the magnetostrictive property (%) is a value calculated by the following equation (2). The cold rolling reduction (%) is a value calculated by the following equation (3). '

 Recovery rate of shape memory characteristics (%)

= 100 X {(ε _d -ε _r ) / ε _ά } · · (1) ε _d : surface strain after deformation

 ε r: Surface distortion when recovered

Magnetostrictive property (%) = 100 X {(L ₂ -Li) / Lx} · · · · (2)

Li: Length before applying magnetic field (mm)

L ₂ : Length after applying magnetic field (mm)

Cold rolling reduction (%) = 100 X {(t!-T2) / t! } · · · (3) t ι: Thickness before cold rolling (mm) t 2: Thickness after cold rolling (mm)

As is clear from Table 4, when Examples 7 to 12 and Comparative Examples 4 to 5 are compared, the invention example shows a shape memory alloy that is more excellent in the recovery rate of the shape memory property, the magnetostriction property and the cold rolling rate. I got it. Inventive Example 7-: Of the L2s, a single-crystal ^ phase single-phase structure (Inventive Examples 9 and 10) and a two-phase structure of ^ phase and second phase (Inventive Examples 11 and 12) make Compared with the single-phase structure of the crystalline ^ phase (Inventive Examples 7 and 8), a ferromagnetic shape memory alloy having more excellent shape memory recovery rate, magnetostriction property and cold rolling rate could be obtained. In addition, as shown in Invention Example 12 which is particularly excellent in processing performance (that is, high in cold rolling ratio) and Invention Example 11 which is excellent in recovery rate of shape memory characteristics and magnetostriction characteristics, the type and amount of the added element are appropriate. It is possible to obtain a ferromagnetic shape memory alloy having the performance according to the purpose and application by selecting the above.

Composition (mass%)-organization of 7 phases

 M

 Co Ni Al Fe Mn Ga In Si B Cr (Volume Inventive Example 1 37.5 33.5 29 One----One-Polycrystalline ^ phase-

Invention Example 2 18 37 25 20 0.003 Polycrystalline / 3-phase ―

Invention Example 3 35 34 28 3 Single crystal phase

Invention Example 4 50 20 22 5 3 Single crystal phase

Invention example 5 39 30.5 26 4.5 0.001 / 3 phase + α phase 10

Invention example 6 26 41 23 5 5/3 phase + 7 phase 40

Comparative Example 1 4 59 37 Polycrystalline three phase

Comparative Example 2 54 4 .. 42 Single crystal phase

Comparative Example 3 60 26 4 5 5 phase +7 phase 80

; Ϋ́ 特性 ΰ ： fl fl fl fl;;;;;;;;;;;;;;;;;;;;; 例; 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例 例Comparative Example 1 Δ XX Comparative Example 2 XXX Comparative Example 3 XX ◎

Shape memory characteristics ◎: Recovery ⁸⁰ % or more

 〇: Recovery § 50% or more, full 80% △: Recovery 20% or more, full 50% X: Recovery less than 20% Magnetostrictive properties ©: 0.2% or more

 Ο: 0.1% or more, 0.2% or less △: 0.01% or more, 0.1% or less X: less than 0.01%

 Cold rolling rate 50% or more

³ 0% or more, δ0% 丰 full

5%未満 5% or more, 30% * full

Less than 5%

 CO

 Organization Phase 2

 Physical fitness

 Co Ga Ni Fe Mn In Si B Cr (Volume

Invention Example 7-35--One----Polycrystalline jS phase One

Invention Example 8 30 + 20 0.003 Polycrystalline / 3-phase ―

Invention Example 9 32.5 Single crystal phase

Invention Example 10 50 29 5 3 Single crystal ^ phase

Invention Example 11 26.5.4.50 0.001; 8 phase + 2nd phase 10

Invention Example 12 24 5 5; 3 phase + 2nd phase 40

Comparative Example 4 4 37 59 Polycrystalline S phase

Comparative Example 5 60 10 25 5; S phase + second phase 80

Shape S3 characteristics Magnetostriction characteristics Cold rolling ratio Invention example 7 △ Δ X

 n

Invention Example 0 Δ Δ X πα η

Invention Example 9 ◎ ◎ Δ Invention Example 10 (Q) Δ Invention Example 11 ◎ ◎ 〇 Invention Example 12 〇

 © Ο © ΔΟΔΧΧ ◎ Comparative Example 4 Δ X X

 Times

Comparative Example 5. X X

 1, ◎ Shape memory characteristics 80% or more

 50% or more, 80% full 20% or more, 50% * less than 20% Magnetostrictive properties ®: 0.2% or more

 Ο: 0.1% or more, 0.2% full Δ: 0.01% or more, 0.1% full X: less than 0.01%

 Cold rolling rate 50% or more

30% or more, 50% full 5% or more, 30% full 5% or less

Industrial applicability

 According to the present invention, it is possible to obtain a ferromagnetic shape memory alloy having excellent ductility, having ferromagnetism, and causing martensite transformation.

Claims

The scope of the claims 1. A composition consisting of 5 to 70 atomic% of Co, 5 to 70 atomic% of Ni, and 5 to 50 atomic% of Al, with the balance consisting of unavoidable impurities and a single-phase structure consisting of / 3 phase of B2 structure Or a ferromagnetic shape memory alloy having a two-phase structure composed of a y phase and a ^ phase having a B 2 structure.  2. A composition containing 35 to 65 atomic% of Co and 20 to 35 atomic% of Ga, with the balance consisting of Ni and unavoidable impurities, and a single-phase structure consisting of ^ phase of B 2 structure or B 2 structure A ferromagnetic shape memory alloy characterized by having a two-phase structure composed of eight phases and a second phase having an fcc structure.  3. The ferromagnetic shape memory alloy according to claim 1 or 2, further comprising 0.001 to 30 atomic% of Fe and 0.001 to 30 atomic% of Z or Mn in addition to the composition. 4. In addition to the above composition, one of Ga, In, and Si is contained in an amount of 0.001 to 50 atomic% or a total of two or more of 0.001 to 50 atomic%. Or a ferromagnetic shape memory alloy according to item 3.  5. In addition to the above composition, 0.001 to 50 at% of one of In and Si or 0.001 to 50 at% of two in total is contained. Ferromagnetic shape memory alloy.  6. In addition to the above composition, B is 0.0005-0.01 atomic%, Mg is 0.0005-0.01 atomic%, C is 0.0005-0.01 atomic%, and P is 0.0005- 6. The ferromagnetic shape memory alloy according to claim 1, wherein the ferromagnetic shape memory alloy contains one or more of 0.01 atomic%. 7. In addition to the above composition, one of Pt, Pd, Au, Ag, Nb, V, Ti, Cr, Zr, Cu, W and Mo is 0.001 ~: 10 atomic% or two or more Total 0.00 :! The ferromagnetic shape description according to claim 1, 2, 3, 4, 5, or 6, wherein the ferromagnetic shape is contained. Alloy.  8. The ferromagnetic shape memory alloy according to claim 1, wherein said single phase structure is a single crystal.  9. The ferromagnetic shape memory according to claim 1, 3, 4, 6, or 7, wherein a volume fraction of the γ phase in the two-phase structure satisfies a range of 0.01 to 80% by volume. alloy. 10 .. The second phase of the dual phase structure is, A 1 of the y phase and / or L 1 ₂ Structure Structure § 'phase and / or the hcp structure .epsilon. C. The ferromagnetic shape memory alloy according to claim 2, 3, 5, 6, or 7, wherein the ferromagnetic shape memory alloy is a phase.  11. The strength according to claim 2, wherein the volume fraction of the second phase in the two-phase structure satisfies the range of 0.01 to 80% by volume. Magnetic shape memory alloy.