JPS62170401A - Microcrystalline alloy produced from solid phase reaction amorphous or disordered alloy powder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to the production of microcrystalline alloys from amorphous or disordered metal alloy powder precursors. More particularly, the present invention relates to the synthesis of microcrystalline alloys from amorphous or disordered metal alloy powders produced by interdiffusion of homogeneous mixed precursors during solid-state reaction methods and novel microcrystalline alloys obtained therefrom. quality composition.

BACKGROUND OF THE INVENTION Microcrystalline alloys have become of interest in the area of structural and engineering materials because of their mechanical, physical, wear and corrosion resistant properties. Each of these alloys has an individual degree of crystallinity, but is characterized by many irregular nucleation sites whose growth is inhibited due to the growth of adjacent nucleation sites. This differs from true crystalline materials, which are the result of continuous growth forming a long-range continuous ordered structure of one nucleation site. The fine grain structure resulting from many small nucleation sites is responsible for the improved mechanical and wear resistance of microcrystalline alloys compared to polycrystalline materials. Microcrystalline alloys can have high tensile strength, high thermal stability and high ductility due to the main properties of the elemental composition of the particular microcrystalline alloy. These materials are of particular interest for applications in tool steel alloys such as cutting tools, dies and other frequent products requiring high strength properties as well as high temperature performance and oxidation resistance.

Microcrystalline alloys can be produced by heat treating an amorphous metal alloy powder at a temperature above the crystallization temperature of the powder. This is sufficient to produce microcrystalline material, but
However, it is carried out for a time not long enough to produce a substantially crystalline material. The compositional range of the amorphous alloy material is retained during the microcrystalline specific heat treatment and is present in the produced microcrystalline material. Therefore, the composition and homogeneity of the amorphous or disordered metal alloy powder precursor determines the extent to which various desired microcrystalline alloy properties such as hardness, ductility, and thermal performance are present in the resulting microcrystalline alloy. .

Most amorphous metal alloy materials are produced from a molten precursor phase by rapid solidification processing (R3P).

The amorphous metal alloy material is then heat treated at a temperature above the crystallization temperature of the material for a time necessary to form the microcrystalline solids.

The R3P process for forming amorphous metal alloys has been recognized as a great commercial success because a variety of known alloys can be produced by this process in a variety of forms, such as thin layers, ribbons, and wires.

The method includes one step of the melt producing the amorphous metal alloy composition.
This includes applying a cooling rate as fast as 0S to 107C/sec. One example of this method is taught by U.S. Pat. is disclosed for quenching metals in the form of amorphous ribbons, thin films, wires or platelets. In order to obtain amorphous or disordered metal alloy powders from RSP production materials, it is necessary to mechanically grind the amorphous metal alloys, for example by chipping, crushing, grinding or ball milling. The resulting powder is then heat treated at a temperature above the crystallization temperature of the amorphous metal alloy for a time necessary to effect crystallization.

U.S. Patent No. 4,400.2 to Ray
No. 12 and No. 4,410,490 respectively disclose the production of cobalt-chromium-carbon and cobalt-nickel-Kungesten-carbon microcrystalline alloys by the R3P method. U.S. Pat. No. 4,473,402 to Ray describes amorphous cobalt powder produced by the R3P process for producing microcrystalline alloys.
Consolidation of chromium-carbide compositions, for example by hot extrusion or cold pressing and sintering, is disclosed. Ray reports a wider composition range of microcrystalline alloy materials than previously achieved. This is based on the use of the R3P-quenching process, which enables high temperature addition from the melt, in this case directly stabilizing the amorphous phase and forming an amorphous alloy. Stabilization by slow temperature reduction can produce a complete or semi-perfect equilibrium and also cause crystallization to occur. Ray manufactures the alloy by melt spinning in all three patents. The resulting alloy is chemically homogeneous, in ribbon form, and must be pulverized to powder form before heat treatment to produce a microcrystalline alloy. Milling results in some loss of uniformity in the resulting amorphous metal alloy powder, and this loss of uniformity characterizes the microcrystalline phase of the composition formed by this method.

Journal of Materials Science
rnal of Materials 5science
), 16.1981, pp. 2924-2930, there are two papers by Ray, ``High-strength microcrystalline alloys produced by devitrification of metallic glasses (formerly gh Stre
ngth Microcrystalline 81lo
To ys Prepare by Devitri
fication of MetallicGla
ss ) J and “Devitrification/thermal consolidation of metallic glasses: new material technology via rapid solidification method (Detriticati
on/11ot Con5olidation o
f Metallic Glass: ^
New Materials Technology v
ia Rapid SolidtcationPr
ocessing) J is included. These articles disclose a method of crushing an amorphous metal alloy spun RS P IJ bond into a powder and hot pressing the powder into the desired microcrystalline form. Microcrystalization occurs during the hot pressing process, which combines the bulk forming process with the heat treatment necessary to form the microcrystalline alloy.

The R3P method of producing amorphous alloys discussed above has the disadvantage that such formed amorphous alloys are produced in defined shapes, ie, as thin layers, such as ribbons, wires, or platelets. Although there are some direct applications for amorphous metal ribbons, as required for the production of microcrystalline alloys, a milling step is most often required to obtain a more easily used amorphous alloy powder. The milling step often results in some degree of loss of uniformity between the ribbon and the powder.

Furthermore, the milling of amorphous alloys and subsequent recombination in the desired bulk shape is a difficult process when realizing many amorphous metal alloys with high mechanical strength and high hardness.

Although the R3P technique increases the range of microcrystalline alloy compositions obtainable over that of the gold equilibrium system, the range is rather narrow because the molten phase of the amorphous alloy precursor material is less displaced from the equilibrium phase. It is.

An alternative to the R3P method is the use of a phase reaction method for the production of amorphous or disordered metal alloy powders.

Such a method is described in the international application PCT/PCT published under the Patent Cooperation Treaty to Johnson et al.
It is disclosed in US 84100035. The method disclosed therein relates to the production of amorphous or microcrystalline materials by solid state reaction. This method involves bringing two or more materials into contact such that they undergo a chemical reaction, resulting in diffusion of the materials into each other, and the materials undergo a chemical reaction, thus causing the formation of a metastable solid. This includes heating to an enabling temperature. Reactions at temperatures near the crystallization temperature can form finely crystalline alloys. The method further requires that the phase formed has a free energy lower than the sum of the free energies of the starting components.

What is lacking in the area of microcrystalline alloy production from powders is a simple method to directly form a variety of microcrystalline alloy compositions from amorphous or disordered metal alloy powders. In particular, there is no simple method for synthesizing directly as a powder an amorphous metal alloy material that can be subjected to direct heat treatment to yield a microcrystalline alloy without loss of homogeneity.

Accordingly, one object of the present invention is to provide new microcrystalline alloy compositions.

Another object of the present invention is to provide a simple method for producing alloy compositions with a variety of homogeneous characteristics.

These and other objects of the invention will become apparent from the following description and examples.

SUMMARY OF THE INVENTION The present invention provides microcrystalline material by heat treating substantially amorphous or disordered metal alloy powders produced by interdiffusion of homogeneous mixed precursor materials during a solid state reaction process at a temperature well above the crystallization temperature. The present invention relates to a method of producing a microcrystalline alloy that includes producing a microcrystalline alloy.

The present invention further provides the method of heat treating substantially amorphous or disordered metal alloy powder produced by interdiffusion of homogeneously mixed precursor materials during a solid state reaction process at a temperature well above the crystallization temperature to form a microcrystalline alloy. The present invention relates to a microcrystalline alloy produced by producing a microcrystalline alloy.

The present invention also relates to a microcrystalline alloy characterized in that the free energy of the alloy is greater than that of a rapidly solidifying material having the same composition, and a method for producing the same.

DETAILED DESCRIPTION In accordance with the present invention, novel compositions of microcrystalline alloys made from substantially amorphous or disordered metal alloy powder precursors made by solid state reaction methods are provided. Using"
The term "fine-grained alloy" refers to an alloy material characterized by a grain size of about 0.01 to about 0.1 microns. The term "amorphous metal alloy" refers to an amorphous metal-containing alloy that may include non-metallic elements. The term "substantially" with respect to amorphous metal alloy powders means that the powder used to make the microcrystalline alloy is at least 50% amorphous, preferably at least 80% amorphous.
% amorphous, most preferably about 100% amorphous.

The method disclosed herein provides for the production of microcrystalline alloys from amorphous or disordered metal alloy powders produced by solid state reaction methods. Solid state reaction processes for amorphous alloys produce alloys in powder form, thus avoiding the need for pulverization and enhancing retention of chemical homogeneity of the amorphous material in the resulting microcrystalline alloy. These solid phase reaction methods result in the direct synthesis of amorphous or disordered metal alloy compositions in a powder form that is quite different from the equilibrium composition. This high non-equilibrium state for the conversion of amorphous metal alloy powders into microcrystalline alloys is such that these processes yield high compositional diversity and microcrystalline alloys with a corresponding diversity in terms of physical properties. influence

A similar method disclosed herein to produce atomic scale dispersion of atoms at high non-equilibrium conditions can be applied to microcrystalline alloys or alloys that are difficult to reach by the R3P method due to the liquid immiscibility of the molten precursor state. It is possible to produce compositions. A uniform and well-dispersed arrangement of alloy atoms can be obtained with this type of solid-state reaction synthesis, which cannot be obtained by the R3P method of immiscible molten metals. This demonstrates the expanded compositional versatility of fine-grain alloys that can be made from amorphous metal alloy powder precursors produced by the solid state reaction process described herein.

The in-phase reaction used can vary depending on the composition and properties of the desired alloy. Some suitable solid state reaction methods include chemical reduction reactions and thermal decomposition reactions. Each reaction method produces a powder alloy composition formed by interdiffusion of the initial components without the need to chemically react them. The composition can be amorphous or can be rendered amorphous by heat treatment at lower temperatures and pressures than are necessary for crystallization. The resulting amorphous or disordered powder is suitable for heat treatment to a microcrystalline phase as taught herein.

Dowa chemical reduction to synthesize amorphous or disordered metal alloy powder precursors is described in U.S. Pat. No. 4,537,625;
Name [Amorphous metal alloy powder and its synthesis by in-phase chemical reduction reaction (Amorphous Metal A11
oy Powdersand 5ynthesis o
f Same by 5solid 5tate Che
Mical Reduction Reactions
) Disclosed in J. The method includes placing a precursor compound in a liquid medium and reducing the compound to obtain a substantially amorphous metal alloy. More specifically, as disclosed, the method includes dissolving a precursor compound in a solvent to form a solution, reducing the compound, and forming a precipitate. This precipitate is a homogeneous mixture of the components of the amorphous alloy being synthesized. Reduction, which occurs preferably in the absence of oxygen and at a temperature below the crystallization temperature, can be carried out by adding a reducing agent to the solution or by other reduction methods such as electrochemical or photocatalytic reduction. Subsequent heat treatment at a temperature below the crystallization temperature of the amorphous metal alloy formed results in a transition to the amorphous phase.

Solid state pyrolysis is another method by which amorphous metal alloys can be formed. U.S. Patent No. 4,537,624, titled “Amorphous metal alloy powder and its synthesis by solid phase decomposition reaction (Amo
rphous Metal A11oy Powder
s and 5ynth, esiof Same by
5solid 5tate Decomposition
n Reactions) teaches such a method. The method includes pyrolyzing the precursor compound at a temperature below the crystallization temperature of the amorphous metal alloy formed. Decomposition of the precursor material can occur in a partial or full vacuum or under an inert, reducing or reactive atmosphere. The precursor components can become alloyed during the decomposition step if the temperature and timing favor alloying of the given components. If no alloying occurs during the decomposition step, a powder is obtained that is a homogeneous mixture of the components of the alloy formed. This is then heat treated at a temperature sufficiently lower than the crystallization temperature of subsequent alloying components to form an amorphous phase.

The solid phase reaction method described above produces amorphous or disordered metal alloy powders with high non-equilibrium conditions. This high free energy state is characterized by higher molecular disorder than the molten phase used in R3P for compounds with similar composition. Solid state reactions generally yield stable amorphous or disordered alloy materials with much greater compositional diversity than can be obtained using the R3P method, which yields materials consisting of equilibrium phase compounds.

The resulting amorphous or disordered alloy powder containing variations in composition due to the high free energy of this material is then heat treated in accordance with this disclosure to produce a microcrystalline alloy. For example, as mentioned above, solid state reaction methods increase the range of compositions present in a given microcrystalline alloy.

By increasing the range of compositions, a commensurate increase in the range of properties for different compositions is achieved, thus making in-phase reactions desirable for the production of microcrystalline alloys.

The amorphous metal alloy powder produced by the above-described in-phase reaction or other solid-state reaction method may be compressed into a desired shape or left in powder form, and the solidus temperature of the amorphous or disordered metal alloy powder may be approximately 0.6 to A microcrystalline alloy can be produced by heat treatment to a temperature of 0.95.

The heat treatment step for microcrystalline solids is about 1 to about 1,0 depending on the amorphous or disordered metal alloy composition used and the processing temperature.
Occurs over a period of 00 hours.

Specific Examples The following examples are given to more fully illustrate the invention, but are not intended to limit it. Examples demonstrate the production of microcrystalline alloys with desired properties characteristic of amorphous or disordered metal alloy powder precursors using amorphous or disordered metal alloy powder precursors produced by solid state reaction methods. .

Example 1 This example illustrates the production of a microcrystalline iron-di-nokeroboron alloy composition from an amorphous or disordered metal alloy powder produced under solid state reduction conditions.

About 14 mmol of nickel chloride NiCl 6 oto and about 16 mmol of iron chloride FeCl z 4HzO are dissolved in about 100 ml of distilled water to form a reaction solution, then 500 mj! Filter into a flask. The reaction vessel was degassed with argon. NaB11. About 50 mmol of argon degassed solution dissolved in about 100 ml of distilled water was then added to about 11
Added over 74 hours. As soon as the sodium borohydride solution was added, hydrogen gas was generated from the solution and a black magnetic precipitate was formed. The reaction solution was stirred for about 16 hours after the addition was completed to ensure complete reaction. The solution was removed from the precipitate with a cannula, and then the precipitate was soaked in distilled water for 5 minutes.
Washed with 12 parts of 0ml. The precipitate is then heated to about 60°C under vacuum.
It was dried for about 4 hours. In this state, the black precipitated powder reacts violently when exposed to oxygen and should therefore be kept free of oxygen.

The powder was then transferred under inert conditions to a quartz tube, which was sealed under vacuum and heat treated at approximately 290° C. for 264 hours. This resulted in a powder consisting essentially of amorphous material.

Further heat treatment of a portion of the powder at about 900° C. for about 1 hour results in silvery agglomerates that are somewhat reactive when exposed to oxygen.

The X-ray diffraction data of the material has an approximate composition of Fe consisting of multiple phases.
A microcrystalline alloy of 5NizB was shown.

Example 2 The procedure described in Example 1 was repeated, but the heat treatment of the amorphous or disordered metal alloy powder to form a microcrystalline alloy was carried out at about 600° C. for about 1 hour.

The resulting alloy was determined to be microcrystalline and to have the same composition as in Example 1, Fe, Ni, and B. This shows that the temperature of this heat treatment simply needs to be well above the crystallization temperature, and that a wide range of temperatures above the crystallization temperature can be used. This temperature range will of course vary depending on the elemental composition of a given amorphous metal alloy powder precursor.

Example 3 Approximately 9.10 g of FeCl 2 .411zO (45,75
mmol) and CoC1z-6H202,856g
(12 mmol) was dissolved in 300 ffl of distilled water. The solution was filtered into 11 Schlenk flasks and degassed with argon. 1.623 g (11.25 mmol) of neodymium powder was added against a countercurrent flow of argon. This rapidly stirred suspension contains NaBHn.
5.49 g (144 mmol) of distilled water 200 mj! The degassed solution was added dropwise over a period of 1 hour. - After stirring overnight, the solution was removed from the black neodymium-containing precipitation mixture with a cannula. This mixture was then diluted with 100 II l of distilled water.
The sample was washed with 1z portion and dried under vacuum at 60° C. for 4 hours. The material was heated to 200° C. for 20.5 hours under reduced pressure to remove H2 from the powder.

The material was then sealed in a quartz tube and heat treated at 840° C., resulting in a microcrystalline material of the composition Nd 15Fe6+ Co I 6all.

Example 4 Cucβ2 2H in an argon-filled drying box
20 and Nal111. A high surface area copper powder precipitate prepared by reacting in water at room temperature under inert conditions 6,
306 g was added to a tetrahydride solution of 0.246 g of 匈(CO)6 under rapid stirring. The solvent was removed and the resulting dry powder mixture was sealed in a quartz tube under vacuum. The material was heat treated at 200°C for 2 hours and then at 300°C for 22 hours. Elemental analysis showed that the resulting powder, with an atomic proportion of CLI 99.3W0.7, contained approximately 2.7% by weight tungsten (measured 2.0% by weight Tigesten). Only copper wires were observed by XvA analysis.

This disordered metal powder was then heat treated at a temperature higher than the crystallization temperature of the powder, resulting in a microcrystalline alloy with the same structure.

The above examples demonstrate the formation of microcrystalline alloy compositions from amorphous or disordered metal alloy powder precursors prepared by solid state reaction methods. This novel application of a solid-state reaction method in which a fine-grained precursor compound is produced as an amorphous or disordered metal alloy powder existing in a high free energy state, followed by a microcrystalline heat treatment process, It can help maintain some of the highly disordered state of the system in the material.

This increases compositional variation over previously known methods of producing microcrystalline alloys, and is also simpler than these previously utilized methods. Additionally, these materials and processing methods can also make the materials useful as toughening aids. The materials that could be modified to produce the new composites were crystalline metal powders,
The scope of the present invention, which can include ceramics and plastics, is intended to include modifications and variations commensurate with the scope of the claims. The parameters shown herein, such as the above and below crystallization temperatures and times shown for amorphous and microcrystalline alloy formation, and the solid state reaction methods shown, are not intended to be limiting.

Procedural Amendment 62.2.10 1988, Month, Day, Commissioner of the Japan Patent Office Black 1) Mr. Yu Aki 1, Indication of the case 1986 Patent Application No. 315913 2, Issued''
``Cod Anka ■嬰天 n%hot zero chichi 7 go 0 powder 13, relationship with the person making the amendment case Applicant's name Title: The Standard Oil Company 4,
Agent 5, date of amendment order, amends the invention specification as follows.

Claims (12)

[Claims] (1) Production of a microcrystalline alloy, which involves heat-treating a substantially amorphous or disordered metal alloy powder produced by a solid phase reaction method at a temperature sufficiently higher than the crystallization temperature to produce a microcrystalline alloy. Method. (2) The method according to claim (1), wherein the solid phase reaction is a chemical reduction reaction. (3) The method according to claim (1), wherein the solid phase reaction is a thermal decomposition reaction. (4) The method of claim 1, wherein the amorphous metal alloy powder is heat treated at a temperature of about 0.6 to about 0.95 of the solidus temperature of the amorphous metal alloy powder. (5) Microcrystals produced by heat-treating a substantially amorphous or disordered metal alloy powder produced by a solid phase reaction method at a temperature sufficiently higher than the crystallization temperature to produce a microcrystalline alloy. quality alloy. (6) The microcrystalline alloy according to claim (5), wherein the grain size of the microcrystalline alloy is within the range of about 0.01 to about 1.0 microns. (7) A microcrystalline alloy characterized in that the free energy of the alloy is greater than the free energy of a rapidly solidifying material of substantially the same composition. (8) A substantially amorphous metal alloy powder produced by a solid phase reaction method and having a high non-equilibrium state is heat treated at a temperature sufficiently higher than the crystallization temperature to convert the powder into a microcrystalline alloy. A method for producing a microcrystalline alloy, characterized in that the microcrystalline alloy maintains a high non-equilibrium state of the amorphous metal alloy powder in the microcrystalline alloy. (9) The method according to claim (8), wherein the solid phase reaction is a chemical reduction reaction. (10) The method according to claim (8), wherein the solid phase reaction is a thermal decomposition reaction. (11) The method according to claim (8), wherein the amorphous metal alloy powder is heat treated at a temperature of about 0.6 to about 0.95 of the solidus temperature of the amorphous metal alloy powder. . (12) A microcrystalline alloy is produced by heat-treating a substantially amorphous metal alloy powder produced by the plane phase reaction method at a temperature sufficiently higher than the crystallization temperature, and the free energy of the alloy is approximately A microcrystalline alloy characterized by a free energy greater than that of a rapidly solidifying material of the same composition.