JPH062016A - Al-ti intermetallic compound powder and its production - Google Patents

Abstract

PURPOSE:To mass-produce the powder having minimum contamination and uniform quality in a short time by mechanically alloying a mixed powder of Al and Ti in a necessary ratio, then heattreating and crushing the alloy. CONSTITUTION:Al and Ti are mixed in an atomic ratio corresponding to the composition of the desired Al-Ti intermetallic compd. powder, and further <=10 atomic % of each element is added. The mixed powder is mechanically alloyed to obtain a composite powder in which Ti is dispersed. The composite powder is then heat-treated, and the treated powder is crushed. Al is preferentially diffused in Ti by the heat treatment, and a uniform-quality powder is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing Al--Ti based intermetallic compound powder and Al--Ti based intermetallic compound powder.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an Al--Ti based intermetallic compound powder, a rapid solidification method, a gas atomizing method, or a method according to JP-A-1-215903 is known.

[0003]

However, the rapid solidification method and the gas atomization method are not suitable for mass production because the melting technique is difficult and they are suitable for small-scale production.

Further, the method of Japanese Patent Laid-Open No. 1-215903 is a method in which mechanical alloying is carried out, but practically it was not possible to obtain a satisfactory intermetallic compound only by carrying out mechanical alloying. That is, in this method, only a composite material powder was obtained in the case of a short-time treatment, and only a powder having an unclear crystal structure was obtained in the case of a long-time treatment. Further, when mechanical alloying is performed for a long time, there is a problem that contamination by Fe, O, N, etc. increases and the material of the treated powder becomes non-uniform.

Therefore, an object of the present invention is to provide an Al-Ti based intermetallic compound powder which can obtain a powder of a uniform material, is suitable for mass production, has a short processing time, and can minimize contamination. Manufacturing method and Al-
To provide a Ti-based intermetallic compound powder.

[0006]

To achieve the above object, the present invention according to claim 1 or 2 provides a ratio (atomic ratio, etc.) corresponding to the composition of the Al-Ti based intermetallic compound powder intended for Al and Ti. ), And optionally other additive elements in an amount of 10 atom% or less, and mechanically alloying the blended powder to obtain a Ti-dispersed composite powder, and then heat-treating the Ti-dispersed composite powder. And then
After that, the heat-treated powder obtained by the heat treatment is pulverized.

In the present invention, Al and Ti are compounded in a predetermined ratio such as an atomic ratio corresponding to the composition of the intended Al-Ti based intermetallic compound powder. Furthermore, if necessary, other additive elements may be mixed in an amount of 10 atomic% or less. That is, for example, 18 wt% or less of Cr and 0.5 wt% or less of B can be added to the total amount of Al and Ti. Here, it is preferable that Ti has a particle size smaller than 200 mesh. Further, Al has a grain size of 32 to 250 mesh and is preferably larger than Ti powder. Further, it is preferable that Cr has a particle diameter smaller than 200 mesh in order to improve diffusion. Instead of individually preparing the Al powder and the Cr powder, an Al-Cr alloy powder may be used. Thus, when using Al-Cr alloy powder,
A particle size of 100 mesh to 250 mesh can be applied. In principle, it is preferable that the content of O ₂ in each powder be 0.5% by weight or less.

Examples of the element to be added include Mn in addition to Cr and B described above.

In the present invention, the above raw materials are mixed in advance and then charged into a mixer. With this mixer, Al
A mixed powder in which Ti, Cr, etc. are uniformly and finely incorporated in a matrix is produced in a short time.

A ball mill, preferably an attritor, is used as the mixer. That is, so-called mechanical alloying is performed to obtain a Ti-dispersed composite material powder. An attritor is a high energy ball mill, an example of which is shown in FIG.

In the attritor 1 of FIG. 1, the rotation of the shaft 2 causes the agitator 3 to rotate, which causes the ball 4 to move. The raw materials are mixed by the movement of the balls 4. During the mixing operation, gas is introduced from the gas inlet 5 to keep the mixed atmosphere constant. Further, cooling water is introduced from the water inlet 6 to keep the temperature constant. In FIG. 1, 7 is a gas outlet and 8 is a water outlet.

The ball 4 has a maximum size of 1 inch, preferably 3
/ 8 inch steel balls are preferred. The ratio of the total weight of the balls to the total amount of powder added is such that the ratio of the total weight of the balls to the total weight of the powder is 150: 1 to 20: 1, preferably 140 :.
It is 1. Also, a lubricant can be added. For example, a commercially available wax lubricant manufactured by ADEKA FINE CHEMICAL CO., LTD. Or aluminum stearate can be used. The lubricant is preferably added in an amount of 0.5% by weight based on the total weight of the powder. The rotation speed of the shaft 2 is 150 rpm or more. The number of revolutions during discharging is 150 rpm or less. Ar or He or the like can be used as the mixed atmosphere. The treatment time is short and is 1 to 20 hours.

The peripheral speed at the tip of the agitator 3 is 3.5 m.
It is necessary to be within / second.

As the balls 4, various kinds of balls such as WC type super hard balls, ceramics such as ZrO ₂ type or SiN ₄ type can be used in addition to steel balls.

It is necessary to strictly observe the above-mentioned mixing conditions. If this mixing condition is not observed, the mixing of Fe due to the abrasion of the balls and the container wall of the mixer becomes significant. Furthermore, since the treated powder becomes too fine, the surface area becomes large and the amount of oxidation per unit weight increases remarkably (this occurs mainly during discharge and collection of the powder). Such an increase in contamination causes inconveniences such as Fe preferentially reacting with Al and melting in a heat treatment process described later. Furthermore, if the mixing conditions become less sweet, A
In this case, Ti, Cr, etc. are not uniformly taken into the l matrix.

In the present invention, the Ti-dispersed composite material powder obtained by the mechanical alloying treatment is subjected to a heat treatment including a heat treatment and a uniform diffusion treatment.

In this heat treatment step, first, the Ti-dispersed composite material powder is degreased and washed.

Next, the degreased and washed Ti-dispersed composite material powder is heat-treated. This heat treatment is performed in an inert atmosphere (in an inert gas such as Ar or He) at 400
It is carried out by maintaining the temperature at ℃ to 700 ℃ for 1 to 10 hours. By this heat treatment, Al preferentially diffuses into Ti by the so-called Kirkendall effect. When a lubricant is used in the mechanical alloying process, the lubricant is fired in a vacuum furnace or in the air before the heat treatment.

Further, in the present heat treatment step, in the case where the composition is required to be particularly uniform, in addition to the above heat treatment, 600 ° C. in an inert atmosphere (in an inert gas such as Ar or He).
The homogenized heat treatment is carried out by holding at 1 to 1,300 ° C. for 1 to 10 hours.

The above-mentioned heat treatment and homogenizing heat treatment may be carried out in the atmosphere when the mixing of oxides does not pose a problem or when oxygen is used as a strengthening element.

In the present invention, the Ti-dispersed composite material powder that has undergone the heat treatment process is pulverized by a ball mill to adjust the product powder to a desired particle size. At this time, crushing is easy due to Kirkendall voids generated by the heat treatment.

[0022]

According to the method for producing an Al-Ti-based intermetallic compound powder of claim 1 or the Al-Ti-based intermetallic compound powder according to claim 2, since no melting equipment is required, the equipment cost is low and the melting is performed. Contamination due to is also prevented. Furthermore, the heat treatment reduces segregation and makes it possible to obtain a homogeneous product powder. Furthermore, unlike the conventional rapid solidification method, it can be mass-produced relatively,
The processing time is short and the contamination can be suppressed to the minimum.

[0023]

【Example】

Example 1 Al and Ti powders were blended to produce an Al ₃ Ti-based intermetallic compound powder. Al is 6 or less than 100 mesh
3% by weight was blended, and Ti was 37% by weight of 200 mesh or less.

In mechanical alloying, the attritor shown in FIG. 1 was used as a mixer. Ball 4 is 3 /
An 8-inch steel ball was used. The ratio of the total weight of the balls to the total weight of the powder was 140: 1. The rotation speed of the shaft 2 was 150 rpm. Ar was used as the mixed atmosphere. The processing time was 2 hours. The peripheral speed of the tip of the agitator 3 was set to 3.5 m / sec or less. FIG. 2 shows the Ti dispersed composite material powder obtained by the mechanical alloying treatment. In the figure, the gray portion shows Ti and the matrix portion shows Al.

Next, the Ti-dispersed composite material powder obtained by the above mechanical alloying treatment was subjected to heat treatment including heat treatment and uniform diffusion treatment.

In this heat treatment step, first, the Ti dispersed composite material powder was degreased and washed.

Then, the degreased and washed Ti-dispersed composite material powder was heat-treated. This heat treatment was carried out by holding at 600 ° C. for 5 hours in an inert atmosphere (in Ar gas). FIG. 3 shows the powder after this heat treatment.
By this heat treatment, Al
It is understood that is diffused preferentially into Ti.

After the above heat treatment, a homogenizing heat treatment was carried out by keeping the temperature at 1,000 ° C. for 10 hours in an inert atmosphere (Ar gas).

Finally, the Ti-dispersed composite material powder that has undergone the heat treatment process was pulverized by the attritor of FIG. 1 to adjust the product powder to a desired particle size. At this time, crushing is easy due to Kirkendall voids generated by the heat treatment. The pulverization was performed in an Ar atmosphere at a rotation speed of 150 rpm for 5 minutes.

As a result, Al of 100 mesh or less is obtained.
₃ Ti-based intermetallic compound powder could be obtained.

Example 2 Al and Ti powders were blended to produce an AlTi-based intermetallic compound powder. Al is 100 mesh or less 36
6% of less than 200 mesh is added.
4 wt% was compounded.

In mechanical alloying, the attritor shown in FIG. 1 was used as a mixer. Ball 4 is 3 /
An 8-inch steel ball was used. The ratio of the total weight of the balls to the total weight of the powder was 140: 1. The rotation speed of the shaft 2 was 250 rpm. Ar was used as the mixed atmosphere. The processing time was 2 hours. The peripheral speed of the tip of the agitator 3 was set to 3.5 m / sec or less. In this embodiment,
A wax type lubricant was used as a lubricant. The addition amount is
It was 0.5% by weight based on the total weight of the powder.

Then, the Ti-dispersed composite material powder obtained by the above mechanical alloying treatment was subjected to heat treatment including uniform heat treatment and uniform diffusion treatment.

In this heat treatment step, first, the Ti-dispersed composite material powder was degreased and washed.

Next, the lubricant was fired on the degreased and washed Ti-dispersed composite material powder. This is 0.1
It was carried out at 400 ° C. for 1 hour in a vacuum of about Torr.

After that, heat treatment was performed. This heat treatment
It was carried out by holding at 500 ° C. for 5 hours in an inert atmosphere (in Ar gas).

Further, after the above heat treatment, a homogenizing heat treatment was performed by keeping the temperature at 1,000 ° C. for 10 hours in an inert atmosphere (Ar gas).

Finally, the Ti-dispersed composite material powder that had been subjected to the heat treatment was pulverized by the attritor of FIG. 1 to adjust the product powder to a desired particle size. At this time, crushing is easy due to Kirkendall voids generated by the heat treatment. The pulverization was performed in an Ar atmosphere at a rotation speed of 150 rpm for 5 minutes.

As a result, Al of 100 mesh or less is obtained.
A Ti-based intermetallic compound powder could be obtained.

Example 3 Powders of Al, Ti and Cr were blended to produce Al ₃ Ti based intermetallic compound powder. Al was 53 wt% of 100 mesh or less, Ti was 35 wt% of 200 mesh or less, and Cr was 12 wt% of 200 mesh or less.

In mechanical alloying, the attritor shown in FIG. 1 was used as a mixer. Ball 4 is 3 /
An 8-inch steel ball was used. The ratio of the total weight of the balls to the total weight of the powder was 140: 1.

First, a composite material having Cr dispersed in a Ti matrix was manufactured. The rotation speed of the shaft 2 is 150r
pm. Ar was used as the mixed atmosphere. The processing time was 1 hour. The peripheral speed at the tip of the agitator 3 is
Within 3.5 m / sec.

Subsequently, Ti--C was added to the Al matrix.
A composite of dispersed r was produced. The rotation speed of the shaft 2 was 150 rpm. Ar was used as the mixed atmosphere. The processing time was 2 hours. The peripheral speed of the tip of the agitator 3 was set to 3.5 m / sec or less.

Next, the Ti—Cr dispersed composite material powder obtained by the above mechanical alloying treatment was subjected to heat treatment including heat treatment and uniform diffusion treatment.

In this heat treatment step, first, the Ti-dispersed composite material powder was degreased and washed.

Next, the degreased and washed Ti-dispersed composite material powder was heat-treated. This heat treatment was performed by keeping the temperature at 500 ° C. for 5 hours in an inert atmosphere (Ar gas).

After the above heat treatment, a homogenizing heat treatment was carried out by keeping the temperature at 1,000 ° C. for 10 hours in an inert atmosphere (Ar gas).

Finally, the Ti-dispersed composite material powder that had been subjected to the heat treatment step was pulverized by the attritor of FIG. 1 to adjust the product powder to a desired particle size. At this time, crushing is easy due to Kirkendall voids generated by the heat treatment. The pulverization was performed in an Ar atmosphere at a rotation speed of 150 rpm for 5 minutes.

As a result, Al of 100 mesh or less is obtained.
₃ Ti—Cr based intermetallic compound powder could be obtained.

[0050]

As is clear from the above, according to the present invention, it is possible to obtain a powder of a uniform material, which is suitable for mass production, has a short processing time, and can minimize contamination. An Al-Ti-based intermetallic compound powder manufacturing method and an Al-Ti-based intermetallic compound powder can be provided.

The Al-Ti-based gold intermetallic compound powder provided by the present invention is a powder of an alloy that is lightweight and has excellent heat resistance, and is expected to be applied to a raw material for valves or turbochargers.

In addition, application to refractory materials, thermal spray materials or other composite materials is conceivable.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating an attritor used in an embodiment of the present invention.

FIG. 2 is a 100 × microscope view for explaining the Ti-dispersed composite material powder obtained in Example 1 of the present invention.

FIG. 3 is a 100 × microscope view for explaining the state of the Ti-dispersed composite material powder obtained in Example 1 of the present invention after heat treatment.

[Explanation of symbols]

 1 Attritor 2 Shaft 3 Agitator 4 Ball 5 Gas inlet 6 Water inlet 7 Gas outlet 8 Water outlet

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[Procedure amendment]

[Submission date] March 23, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating an attritor used in an embodiment of the present invention.

FIG. 2 is a 100 × micrograph illustrating the Ti-dispersed composite powder structure obtained in Example 1 of the present invention.

FIG. 3 is a 100 × micrograph for explaining the structure of the Ti-dispersed composite material powder obtained in Example 1 of the present invention after heat treatment.

[Explanation of symbols] 1 Attritor 2 Shaft 3 Agitator 4 Ball 5 Gas inlet 6 Water inlet 7 Gas outlet 8 Water outlet

Claims (2)

[Claims] 1. Al-Ti intended for Al and Ti
Blended in a ratio corresponding to the composition of the system intermetallic compound powder, and further optionally blending other additive elements in an amount of 10 atomic% or less, and mechanically alloying the blended powder to obtain a Ti-dispersed composite material powder, Thereafter, the Ti-dispersed composite material powder is heat-treated, and then the heat-treated powder obtained by the heat-treatment is pulverized. 2. An Al—Ti based intermetallic compound powder produced by the production method of claim 1.