WO2005098071A1

WO2005098071A1 - Method of atomizing alloy crystal grain by hydrogen treatment

Info

Publication number: WO2005098071A1
Application number: PCT/JP2005/005587
Authority: WO
Inventors: Masuo Okada; Hitoshi Takamura; Atsunori Kamegawa; Junya Takahashi; Takao Funayama
Original assignee: Tohoku Techno Arch Co., Ltd.
Priority date: 2004-04-08
Filing date: 2005-03-25
Publication date: 2005-10-20
Also published as: EP1749896A1; EP1749896A4; CN1942600A; JPWO2005098071A1; US20070006950A1

Abstract

A technology for atomizing the crystal grains of alloy whose main constituents are elements exhibiting weak affinity with hydrogen. With respect to the alloy whose main constituents are elements exhibiting weak affinity with hydrogen in which an element exhibiting strong affinity with hydrogen is contained, resulting from attaining of presence of an element exhibiting strong affinity with hydrogen in an alloy whose main constituents are elements exhibiting weak affinity with hydrogen, any crystal grains of the alloy can be super-atomized by subjecting the alloy to heat treatment involving hydrogen absorption and release, thereby realizing super-high strength thereof. Thus, the properties of the alloy can be improved and enhanced.

Description

Method for refining alloy crystal grains by hydrogen treatment

Technical field

The present invention relates to an alloy mainly composed of an element having a low affinity for hydrogen, and provides a method for ultra-fine crystal grains by hydrogen treatment and an effective alloy therefor.

Background art

[0002] As a method of improving the mechanical properties and workability of an alloy, there is a method of reducing the crystal grain size. As a method for refining the crystal grain of alloys, a combination of cold rolling and recrystallization, ECAP (Equal Channel Angular pressing) method, strong strain processing such as repeated lap rolling, liquid quenching method, etc. A method of performing heat treatment after processing is known! /

[0003] However, the crystal grain refinement method using these methods has a crystal grain size of about 1 μm, and there is a limit to further improving the crystal grain refinement effect. On the other hand, alloys whose main component is an element with low affinity for hydrogen are expected to have even higher strength due to the refinement of crystal grains (Fig. 1).

[0004] As a method of grain refinement, hydrogen is used in Nd-Fe-B-based compound magnets, Ti-A to V-based alloys, Mg-Al-based alloys, etc., whose main element is an element having a strong affinity for hydrogen. A method has been reported in which a crystal grain is refined by performing a heat treatment for absorbing and releasing (hydrogen absorbing and releasing heat treatment). However, the effectiveness of this method has not yet been confirmed for alloys whose main element is an element having a low affinity for hydrogen.

Disclosure of the invention

Problems to be solved by the invention

[0005] An object of the present invention is to provide a technique for causing an alloy mainly containing an element having a low affinity for hydrogen to contain an element having a high affinity for hydrogen, thereby exhibiting a crystal grain refining effect. .

[0006] The inventors of the present invention have conducted various studies to achieve the above object. As a result, the inventors have found that an alloy containing an element having a low affinity for hydrogen as a main component and an alloy containing an element having a high affinity for hydrogen is contained. On the other hand, when the melting point of a metal (or alloy) expressed in absolute temperature is expressed as T, By placing the alloy in a hydrogen atmosphere at a temperature range of 0 ° C to 0.8T, hydrogen is absorbed, and elements contained in the alloy and having a strong affinity for hydrogen react with the absorbed hydrogen. And found.

[0007] Furthermore, by releasing hydrogen in a temperature range of 0 ° C. to 0.8 T from an alloy mainly containing an element which absorbs hydrogen based on the above findings and has a low affinity for hydrogen, the alloy is released. It has been found that the crystal grain size of can be reduced to 1 IX m or less.

[0008] That is, alloy systems to which the heat treatment for absorption and desorption of hydrogen can be applied include alloys mainly composed of elements having low affinity for hydrogen, alkali metals having strong affinity for hydrogen, such as Li and Na, and Mg. Alkaline earth metals such as Ca and Ca, rare earth metals such as La and Ce, periodic table of elements represented by Ti, V, etc. Group 3-5 transition metal and Pd force Group force At least one or more selected It is characterized by including.

According to the present invention, the following aspects are provided.

[1] For an alloy containing an element with a low affinity for hydrogen as a main constituent element and containing an element with a high affinity for hydrogen, the alloy has a temperature range of 0 ° C to 0.8T. (T is the melting point of the metal or alloy expressed in absolute temperature), and the heat that absorbs and desorbs hydrogen, including releasing hydrogen in the temperature range of 0 ° C-0.8T. A method for refining the crystal grain of an alloy, comprising performing a treatment.

[2] As an alloy system to which hydrogen absorption / desorption heat treatment can be applied, the elements with weak affinity for hydrogen include the elements in the Periodic Table Group 6-10 of the elements represented by Cr, Mn, Fe, Co, and Ni (however, And elements other than Pd), and alloys containing a range of elements selected from the periodic table 11-15 elements of the periodic table of elements represented by Cu, Ag, Au, Zn, and Al. The method for refining crystal grain of an alloy according to the above [1].

[3] As an alloy system to which heat treatment for hydrogen absorption and desorption can be applied, alkali metals with strong affinity for hydrogen, such as alkali metals such as Li and Na, alkaline earth metals such as Mg and Ca, rare earth metals such as La and Ce, Ti, Periodic table of elements represented by V, etc. Group 3-5 transition metal and Pd group power At least one selected from the group consisting of crystals of the alloy according to [1] or [2] above Grain refining method.

[4] Obtained by performing the method for refining the crystal grain of the alloy described in [1]-[3] above and A grain refined alloy, wherein the crystal grains of the alloy have been refined by heat treatment.

The invention's effect

[0010] The present invention provides an alloy mainly composed of an element having a weak affinity for hydrogen by absorbing and desorbing hydrogen, so that a crystal of several tens of millimeters, which was impossible with the conventional method, was obtained. It offers an innovative way to achieve grain. By performing the treatment according to the present invention, the crystal grains of the alloy can be refined, and an alloy material having high strength and an alloy material having improved workability can be obtained.

[0011] Other objects, features, excellence and aspects of the present invention will be apparent to those skilled in the art from the following description. It should be noted that the description in the present specification, including the following description and specific examples, shows preferred embodiments of the present invention, and is described only for the purpose of explanation. It was understood! Various changes and modifications or alterations (or modifications) within the spirit and scope of the invention disclosed herein will be made by those skilled in the art based on the following description and knowledge from other portions of the specification. Will be readily apparent.

Brief Description of Drawings

FIG. 1 is a correlation diagram between the crystal grain size and the material strength, which indicates that the strength is further increased by refining the crystal grains.

FIG. 2 is a powder X-ray diffraction diagram showing appearance phases depending on the treatment temperature after hydrogen absorption treatment of a 7.8 wt% Mg alloy of A alloy.

FIG. 3 is a powder X-ray diffraction diagram showing appearance phases depending on a treatment time after hydrogen absorption treatment of a 7.8 wt% Mg alloy.

[Figure 4] A transmission micrograph after hydrogen absorption treatment of 7.8wt% Mg alloy with fine MgH

There are two phases.

FIG. 5 is a powder X-ray diffraction diagram showing appearance phases depending on a release treatment time after hydrogen absorption and release treatment of a 7.8 wt% Mg alloy.

FIG. 6 is a transmission micrograph of a 7.8 wt% Mg alloy after hydrogen absorption / release treatment, and the alloy structure is refined to about 10 nm. FIG. 7 is a powder Etsoda diffraction diagram showing the appearance phases of the Ato x wt% Mg alloy (x = 3, 5, 7.8) after the hydrogen absorption treatment. It was confirmed that the MgH phase appeared in all compositions and that this treatment method was effective.

2

Shows

FIG. 8 shows the change in the V content of the parent phase with the treatment temperature after the hydrogen absorption treatment of the Fe_10wt% V alloy.

FIG. 9 is a transmission micrograph of a Fe-10 wt% V alloy after a hydrogen absorption treatment at 250 ° C., where fine V-containing precipitates of about 10 nm are present.

FIG. 10 is a powder X-ray diffraction diagram before, after hydrogen absorption treatment and after hydrogen release treatment of an Fe-10wt% V alloy.

FIG. Ll is a powder X-ray diffraction diagram before, after hydrogen absorption, and after hydrogen release treatment of a Cu-5wt% Mg alloy.

BEST MODE FOR CARRYING OUT THE INVENTION

[0013] The present invention provides a technique for subjecting an alloy mainly composed of an element having a low affinity for hydrogen to a hydrogen treatment to refine crystal grains of the alloy. This alloy grain refinement technology includes ultrafine graining technology with a refined grain size of lOnm-l ^ m, and in some cases 10 nm-0.5 μm. Further suitable alloy systems are (A) alloys containing (1) an element having a weak affinity for hydrogen as a main component and (2) containing an element having a strong affinity for hydrogen, and (B) ) The alloys of (A) also include alloys which have been subjected to the present hydrogen absorption / hydrogen release treatment to have a refined crystal grain size. This alloy crystal grain refinement technology involves blending an element having a strong affinity for hydrogen by vigorously utilizing the properties of an alloy having an element having a weak affinity for hydrogen as a main constituent element. This includes selecting an appropriate blending amount and selecting a metal species to be blended appropriately, and also includes a technique for selecting processing conditions for the hydrogen absorption / hydrogen release treatment. In short, all alloys that have an element with a low affinity for hydrogen as the main component and that obtain the desired results (techniques, methods, etc.) by applying the alloy grain refinement described in this specification are all It may be included.

[0014] An element having a low affinity for hydrogen or an alloy composed of only such an element is a force that makes it difficult to absorb hydrogen. For example, by containing 0.1 wt% or more, an alloy capable of absorbing hydrogen is obtained. The alloy usually forms a single phase solid solution or a mixed phase structure of two or more phases including the solid solution. The present invention provides a technique for refining the crystal grains of an alloy mainly composed of an element having a low affinity for hydrogen. In contrast to alloys whose main component is an element that has a low affinity for hydrogen, elements and phases that have a high affinity for hydrogen are made to exist there, and as a result, the main component is a V ヽ element that has a low affinity for hydrogen. In alloys that have a strong affinity for hydrogen and contain elements, heat treatment for absorbing and releasing hydrogen can make the alloy crystal grains ultra-fine, It can be super-strengthened. It is possible to improve the properties of the alloy.

[0015] The element has a weak affinity for hydrogen! The elements are the periodicities of elements represented by Cr, Mn, Fe, Co, and Ni. Table 6-10 Group elements (however, elements other than Pd) and Cu The group force can be selected from the range of elements in the Periodic Table 11-15 elements of the periodic table of elements represented by Ag, Au, Zn, and Al. The element which has a low affinity for hydrogen in the present alloy may include one kind in the alloy! /, And two or more kinds include more elements. You can! /.

[0016] Periodic Table of Elements 6—Group 10 elements include Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co,

Rh, Ir, Ni, Pt and the like. Examples of the elements of the 11th to 15th groups of the periodic table include Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Sb, and Bi. Typically, from the viewpoint of use as a structural material, the main component is selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Ag, Au, Zn, Al, etc. Things. Cr-based alloy, Mn-based alloy, Fe-based alloy, Co-based alloy, Ni-based alloy, Cu-based alloy, Zn-based alloy, A1-based alloy, Ag-based alloy, Au-based alloy, N-to-Cr-based alloy, N-to-Co-based alloys, Cr-Mn-based alloys, N-to-Fe-based alloys and the like may be included.

[0017] Elements having a strong affinity for hydrogen include alkali metals such as Li and Na, alkaline earth metals such as Mg and Ca, rare earth metals such as La and Ce, and periods of elements represented by Ti and V. Table 3—Group strength consisting of Group 5 transition metals and Pd ranges can be selected. The alloy having a high affinity for hydrogen to be added to the alloy for the application of the grain refinement technology of the present alloy may include one kind in the alloy, or two or more kinds. It may be included. [0018] Examples of the alkali metal element include Li, Na, K, Rb, and Cs. Examples of the alkaline earth metal element include Mg, Ca, Sr, and Ba. Examples of transition metals of Group 3-5 of the Periodic Table of Elements include Sc, Y, Ti, Zr, Hf, V, Nb, Ta, rare earth metals, and misch metals. Rare earth metals include lanthanoids and actinoids, and examples of lanthanoids include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Examples include Ac and Th. Typically, it can be selected from those that do not adversely affect the base material, and can be appropriately selected in consideration of inexpensive materials, materials having high affinity for hydrogen, and the like. Preferably, for example, Li, It can be selected from the group consisting of Na, Mg, Ca, La, Ce, misch metal, Ti, V, etc.

[0019] The content of the element having a strong affinity for hydrogen in the alloy system to which the present invention can be applied may be 0.1% or more in total. In some cases, the content of elements with strong affinity for hydrogen is 0.1-45 wt%, in other cases 0.1-35 wt%, or 0.1-25 wt%, typically 1-145 wt%, in other cases May be 2 to 35 wt%, or 5 to 25 wt%, or even 4 to 25 wt%, and in other cases, 5 to 20 wt%, or 5 to 15 wt%. It is possible to determine an appropriate value as appropriate by conducting experiments in accordance with the disclosure of the above, and it is also possible to change it according to the combination (an element having a low affinity for hydrogen) to be combined, Preferred

[0020] The alloys to which the present invention can be applied include B, C, Si, N, P, As, O, S, Se, Te, and B in the periodic table of elements as long as the intended purpose, effect, or action can be obtained. It may include one selected from the group consisting of F, C, B, I, and Be. In the case where the present invention is applied to obtain excellent physical properties, the contents of these elements are not particularly limited.

[0021] As described above, Nd-Fe-B-based compound magnets, Ti_A V-based alloys, Mg_Al-based alloys, etc. have a strong affinity with hydrogen! For intermetallic compounds containing many elements, there are known examples of crystal grain refinement using the method of absorbing and releasing hydrogen.However, alloys mainly composed of elements that have a low affinity for hydrogen are not suitable for hydrogen. There is no disclosure of a specific example based on the absorption / release method of the above.

[0022] The alloy crystal grain refining technology includes a process of absorbing hydrogen into the alloy. In order for this alloy to absorb hydrogen, the alloy must be placed in a hydrogen atmosphere of at least one atmosphere. Process at 0 ° C-0.8T. The minimum temperature is defined as a value that has a reaction rate at which hydrogen absorption proceeds sufficiently, and the maximum temperature is determined by the alloy phase related to the element having strong affinity with hydrogen contained in each alloy. It is desirable to perform the reaction at a temperature lower than the temperature at which the gasification proceeds. Typical temperature ranges in this hydrogen absorption process include 10-800 ° C, and in some cases, 50-700 ° C, 100-600 ° C, or 200-500 ° C. Of course, an appropriate range can be selected depending on the alloy composition. Examples of suitable temperature ranges for the hydrogen absorption treatment include 200 to 450 ° C, or 300 to 400 ° C.

[0023] The hydrogen can be subjected to a hydrogen absorption treatment in a hydrogen atmosphere of at least 1 atm. However, an appropriate value of the pressure of the hydrogen-containing atmosphere or the like can be selected according to an element having a strong affinity for hydrogen. For example, 0.1-20 MPa hydrogen atmosphere, or 0.1-lOMPa hydrogen atmosphere, 0.1-5 MPa hydrogen atmosphere, 0.1-IMPa hydrogen atmosphere, 0.2-2 MPa hydrogen atmosphere, 5-lOMPa hydrogen atmosphere, etc. There is also.

[0024] The time taken for the hydrogen absorption treatment may be appropriately set as long as the intended purpose, effect, or action is obtained, or may be set appropriately as appropriate for the target alloy system. It can be set to an appropriate time depending on other conditions such as the hydrogen pressure and the processing temperature. The processing time can be determined taking into account the economics and efficiency.For example, 0.1 hours and 1 month, in some cases 0.5 hours and 12 weeks or 1 hour and 1 week, and in a preferred example, 1 hour and 1 week Hours – 5 days or 1.5 hours – 5 days, typical examples are 10-120 hours, 15-100 hours or 20-75 hours.

[0025] When this alloy absorbs hydrogen, a chemical reaction may proceed in which some or all of the alloy phase related to an element having a strong affinity for hydrogen forms a hydride or hydrogen solid solution phase. desirable.

[0026] The present alloy crystal grain refinement technology includes a process of releasing hydrogen from an alloy that has absorbed hydrogen. For example, the above hydrogen-absorbed alloy is subsequently released under a thermodynamic equilibrium pressure, preferably under a hydrogen pressure of 1 atmosphere or less, in a temperature range of 0 ° C-0.8T. Of course, hydrogen can be released in the temperature range of 200 ° C-0.8T. Atmosphere should be evacuated if possible, and as much as possible considering crystal grain growth It is desirable to release hydrogen at low temperatures.

[0027] As described above, it is desirable that part or all of the alloy that has absorbed and released hydrogen be reformed in the same appearance phase as before the hydrogen absorption reaction.

[0028] By absorbing hydrogen as described above, a hydride or hydrogen solid solution phase is formed in the alloy, and after hydrogen release, a part or all of the phase appears in the same appearance phase as before the hydrogen absorption reaction. By re-forming, the crystal grains are refined to 1 m or less. By applying the present invention, the crystal grain size of the alloy can be reduced to the submicron order, for example, to about 0.1 to 0.2 m. In some cases, the alloy obtained by the treatment according to the present invention is, for example, one having a refined grain size of 10 nm-1 μm. Further, examples of the obtained alloy include those having a refined crystal grain size of 0.1 to 0.5 m.

[0029] Typical examples of alloy systems to which the heat treatment for absorbing and releasing hydrogen of the present invention can be applied are as follows:

A Mg-based alloy will be described. In the present Mg-based alloy, the amount of Mg can be, for example, 10 wt% or less, and in other cases, it may be about 3 wt%. Strengthening, the Mg content may be 0.1-10 wt%, typically 3-8 wt%, in other cases 3-5 wt%, or 2-4 wt%! / ,.

[0030] Similarly, in the Fe-V alloy, the blending amount of V can be, for example, 15 wt% or less, and in other cases, it can be about 5%. By virtue, the V content may be 0.1-15 wt%, typically 3-10 wt%, in other cases 4-1 10 wt%, or 416 wt%.

[0031] In the Cu-Mg alloy, the compounding amount of Mg may be, for example, 10 wt% or less, and may be about 6 wt% in another case. As a rule, the Mg content may be 0.1-10 wt%, typically 3-8 wt%, in other cases 3-6 wt%, or 4-5 wt%.

[0032] A material in which it is difficult to reduce the crystal grain size of the alloy using the alloy crystal grain size reduction technology of the present invention, the crystal grain size can be reduced, or the crystal grain size is extremely reduced. This greatly improves the mechanical properties, such as electromagnetic properties, workability, and hydrogen absorption / desorption characteristics. In addition, the material having the fine crystal grains is used as a nanotechnology material by utilizing the fine grains, or the coating particles, catalyst particles, and electrodes are used by utilizing the ultra-fine crystal grains themselves. It is expected that it can be used as a thin wire material, compounding material, etc. Also, with the alloy crystal grain size reduction technology of the present invention, alloy powder, It can be expected that the properties described above can be significantly improved for the properties near the surface of the alloy and fine wires.

[0033] In the present specification, the mechanical properties of an alloy (material) 'workability' refers to the mechanical response exhibited by the alloy material and the simplicity of product manufacturing using the alloy material 'reliability' The degree of aesthetics Examples include heat resistance, high temperature strength, corrosion resistance, ultra-high strength, including elastic limit, yield stress, tensile strength, elongation, cross-sectional reduction, hardness, impact value, creep rate, fatigue limit, and so on. Hardness, brittleness, fracture resistance, fatigue resistance, low-temperature brittleness, superplasticity, weldability, weatherability, press workability, design, printability, fingerprint resistance, lubricity, adhesion, abrasion resistance It may also refer to properties related to improvement in durability, durability, and material reliability. The electromagnetic properties may include electrical conductivity, resistance properties, magnetic properties, and the like. The hydrogen storage / release characteristics may include a hydrogen storage / release speed, a hydrogen storage / release temperature, durability, and the like.

[0034] In the present specification, the "periodic table of elements" is a notation used in 1989 with the revision of the inorganic chemical nomenclature of the International Union of Pure Applied Chemistry (IUPAC). Refers to what follows.

Example

Hereinafter, the present invention will be described in detail with reference to Examples. However, the Examples are merely provided for describing the present invention and for referencing specific embodiments thereof. These exemplifications are not intended to limit or limit the scope of the invention disclosed herein. It is to be understood that the invention is capable of various embodiments based on the teachings herein.

[0036] All examples, unless otherwise described in detail, have been or can be performed using standard techniques, which are well known and routine to those of ordinary skill in the art. What is.

[0037] A1 was selected as an element having a low affinity for hydrogen, and Mg was selected as an element having a high affinity, and an alloy powder was prepared for a 7.8 wt% Mg alloy mainly composed of A1. The obtained alloy powder was subjected to a hydrogen absorption treatment under a hydrogen atmosphere of 7.5 MPa in a temperature range of 250 to 450 ° C. for 72 hours. FIG. 2 shows the result of measuring the appearance phase of the obtained alloy by powder X-ray diffraction. By supplying 7.8 wt% Mg alloy to a hydrogen atmosphere in the temperature range of 300 to 400 ° C, the MgH phase Appears, and the dissolved Mg is hydrogenated to MgH, and the alloy is disproportionated to A1 and MgH.

twenty two

It became clear.

Next, hydrogen absorption treatment was performed at 350 ° C. where hydrogenation proceeds for 24 to 72 hours, and an optimum time was determined. Figure 3 shows the results of the appearance of the obtained alloy measured by powder X-ray diffraction. From the change of the lattice constant of A1 with increasing time, it became clear that the Mg content of the A1 solid solution phase also changed. In particular, it can be estimated that the lattice constant force of the A1 alloy is reduced by reducing the amount of Mg in the 7.8 wt% Mg alloy by the hydrogen atmosphere treatment for 24 hours or more (Table 1).

[Table 1] Change in lattice constant of AI and amount of solid solution in Mg by hydrogen absorption treatment time

FIG. 4 shows a transmission electron microscope image after the hydrogen absorption treatment at 350 ° C., 72 h, and 7.5 MPa. MgH

The MgO phase resulting from 2 is finely dispersed, and it is considered that this phase was formed by oxidation of the MgH phase during the preparation of the sample for electron microscopic observation. Therefore, MgH is finely dispersed in A1

twenty two

It is determined that they are dispersed.

Following the hydrogen absorption treatment, the alloy was subjected to a hydrogen release treatment by evacuation at 350 ° C. for 30 minutes and 5 hours. Fig. 5 shows the results of measurement of the appearance phase of the obtained alloy by powder X-ray diffraction. More than 2 hours, it became the same as the appearance phase before hydrogen absorption

FIG. 6 shows a transmission electron microscope image of the alloy that has been subjected to the evacuation at 350 ° C. for 4 hours in this hydrogen release treatment. It was clarified that the grain size of the structure of the obtained alloy was reduced to several tens of millimeters.

[0043] As an example of the present invention, an example in which hydrogen is absorbed at 350 ° C and hydrogen is released at 350 ° C has been described. However, it is possible to disperse hydride finely and release hydrogen at as low a temperature as possible. Crystal grains Is further refined.

[0044] As an example of the case where the content of the element having low affinity for hydrogen is at least effective in the present invention, Fig. 7 shows the hydrogen content of the alloy X wt% Mg alloy (x = 3, 5, 7.8) with the Mg content changed. The X-ray powder diffraction pattern after the absorption treatment is shown. MgH phase appeared in all compositions and only 3 wt% in A1

2

This shows that this treatment method is effective even with a large amount of Mg. Furthermore, from the results of X-ray diffraction measurement, the lattice constant of the alloy returned to the value before hydrogen treatment by the subsequent hydrogen release heat treatment, so that the Mg element that formed the hydride was re-dissolved in the original alloy composition. Helped. It can be seen that the present invention is effective even with an Mg force of S3 wt%.

[0045] A Fe_10wt% V alloy having low affinity for hydrogen, Fe as an element, strong affinity !, V as an element, and Fe as the main composition was selected as the hydrogenation treatment of the present invention at 7.5MPa hydrogen. Hydrogen absorption treatment was performed in an atmosphere at a temperature range of 100 to 450 ° C for 72 hours. FIG. 8 shows the V content of the mother phase of the obtained alloy, which was calculated from the lattice constant of the powder X-ray diffraction measurement. By applying the Fe-10wt% V alloy to a hydrogen atmosphere at 250 ° C, the V content of the parent phase was significantly reduced as compared with other processing temperatures. From this, it was found that a phase containing more V with a larger atomic radius than Fe was precipitated from the Fe-10wt% V alloy phase by the hydrogen absorption treatment at 250 ° C. FIG. 9 shows a transmission electron microscope image of the alloy obtained by the hydrogen absorption treatment. It was clarified that about 10 mm fine precipitates containing more V than the parent phase showing white contrast existed.

FIG. 10 shows the results of X-ray diffraction measurement of the alloy before the treatment, after the hydrogen absorption treatment at 250 ° C., and subsequently subjected to the hydrogen release treatment by forced exhaustion. As shown in Fig. 8, the lattice constant was reduced by the hydrogen absorption treatment where the lattice constant before the treatment was 0.2876 nm, and the lattice constant was restored to the original lattice constant of 0.2876 by the hydrogen release treatment. . This is an example showing that a phase containing a large amount of V element with strong hydrogen affinity is precipitated by the hydrogen absorption treatment, and this precipitated phase disappears by the subsequent hydrogen release treatment, and the alloy composition can be restored to the original one. .

[0047] As examples of these other alloys, Cu is selected as an element having a low affinity for hydrogen, and Mg is selected as an element having a high affinity. Cu is mainly composed of a Cu-5% Mg alloy. Fig. 11 shows the results of X-ray diffraction measurement after the hydrogen absorption treatment and the hydrogen release treatment. Before processing It can be seen that a phase with a smaller lattice constant than this phase newly appeared after the hydrogen absorption treatment in which only the Cu-5% Mg phase was observed, and was restored to the original alloy phase by the subsequent hydrogen release treatment. Therefore, a case in which a similar phase change occurs also in this alloy system was obtained.

[0048] By implementing the alloy crystal grain refinement technology of the present invention, the crystal grain size of an aluminum alloy expected as a lightweight practical alloy can be reduced to the submicron order, for example, to about 0.1-10 / zm, or even more. Can be miniaturized to about 0.05-1.0 / zm. In addition, by implementing the alloy grain refinement technology of the present invention, the crystal grain size of a copper alloy expected as a functional practical alloy can be reduced to the submicron order, for example, to about 0.1 to 10 m, or even more. It can be miniaturized to about 0.1-1.5 / zm. Similarly, by implementing the alloy grain refining technology of the present invention, the crystal grain size of iron group alloys expected as various functional alloys' superalloys as steel materials is on the order of submicron, for example, 0.01-5. m, or even down to about 0.01-0.2 μm.

According to the present invention, it is possible to reduce the crystal grain size of a material in which it was difficult to reduce the crystal grain size of the alloy, and as a result, mechanical properties such as “electromagnetic properties” and “workability” were reduced. Since it is possible to greatly improve the material, it can be expected to be effective in using promising materials that were difficult to process and use in the past.

Industrial applicability

[0050] Development of new materials is strongly demanded from the viewpoints of weight reduction, high functionality, super strength, aesthetics and tactile sensation, and it is difficult to manufacture and process such alloy materials even though they are promising alloy materials from this viewpoint. Because of this, it is possible to solve such problems by reducing the crystal grain size of the alloy, which can be used for applications that cannot be applied. INDUSTRIAL APPLICABILITY The present invention makes it possible to improve the mechanical properties and workability of an alloy mainly composed of an element having a low affinity for hydrogen, so that it can be used for various applications.

It is clear that the present invention can be practiced other than as specifically described in the above description and examples. Many modifications and variations of the present invention are possible in light of the above teachings, and so are within the scope of the appended claims.

Claims

The scope of the claims

[1] Compared to alloys that have a low affinity for hydrogen and contain an element whose main component is an element and contain an element that has a strong affinity for hydrogen, the alloy has a temperature of 0 ° C-0.8T. Absorb and release hydrogen, including absorbing hydrogen over a temperature range (T represents the melting point of the metal or alloy expressed in absolute temperature) and then releasing hydrogen over a temperature range of 0 ° C-0.8T A method for refining the crystal grain of an alloy, comprising performing a heat treatment for causing the crystal grain to be refined.

[2] As an alloy system to which heat treatment for absorption and desorption of hydrogen can be applied, the elements with weak affinity for hydrogen include the elements in the Periodic Table Group 6-10 of the elements represented by Cr, Mn, Fe, Co, and Ni ( However, it is mainly characterized by alloys containing the range of elements selected from the periodic table 11-15 elements of the periodic table of elements represented by Cu, Ag, Au, Zn and Al). The method for refining the crystal grain of an alloy according to claim 1, wherein

[3] Alloys that can be subjected to hydrogen absorption / desorption heat treatment include alkali metals such as Li and Na, which have strong affinity for hydrogen, alkaline earth metals such as Mg and Ca, rare earth metals such as La and Ce, Ti, 3. A crystal grain of the alloy according to claim 1, wherein the alloy contains at least one selected from the group consisting of transition metals of Groups 3 to 5 and Pd of the periodic table of elements represented by V and the like. Method.

[4] An alloy having a weak affinity for hydrogen !, which is an alloy containing an element as a main component and containing an element having a strong affinity for hydrogen. Absorption of hydrogen in the temperature range of ° C-0.8T (T is the melting point of the metal or alloy in absolute temperature), followed by the release of hydrogen in the temperature range of 0 ° C-0.8T. A grain refined alloy obtained by performing a heat treatment for absorbing and desorbing hydrogen, wherein the crystal grain of the alloy is refined by the heat treatment.

[5] As an alloy system to which the heat treatment for absorption and desorption of hydrogen can be applied, the elements with weak affinity for hydrogen include the elements in the Periodic Table Group 6—10 of the elements represented by Cr, Mn, Fe, Co, and Ni ( However, it is mainly characterized by alloys containing the range of elements selected from the periodic table 11-15 elements of the periodic table of elements represented by Cu, Ag, Au, Zn and Al). 5. The alloy according to claim 4, wherein

[6] Li and Na, which have strong affinity for hydrogen, Any group of alkali metals, alkaline earth metals such as Mg and Ca, rare earth metals such as La and Ce, Group 3-5 transition metals of elements represented by Ti, V, etc. 6. The alloy according to claim 4, comprising at least one of the following.

The alloy according to any one of claims 416, wherein the refined grain size is 10 nm to 10 m.