JPS62256902A - Intermetallic al3ti powder and its production - Google Patents

Abstract

PURPOSE:To obtain intermetallic compd. Al3Ti powder for sintering which has small crystal grains and contains less deposited and segretated materials by compounding specific ratios of Al and Ti, heating and melting the compd. in an inert atmosphere, ejecting the melt to a cooling body to quickly solidify the melt, then grinding the solidified compd. CONSTITUTION:After 62-63wt% Al and the balance Ti are charged into a crucible 1, the inside of a vessel 3 is evacuated to a vacuum and an inert gas is introduced therein from an introducing mechanism 7. The raw materials in the crucible 1 are melted and alloyed by a heating mechanism 5. The molten alloy is ejected from a nozzle 4 onto the cooling body 2 such as rotating roll and is quickly solidified to a flake state at a cooling rate of >=10<4> deg.C/sec. The flaky solidified material is processed with a ball mill, etc., by which the material is pulverized. The intermetallic compd. Al3Ti powder which has uniform quality and is suitable for powder metallurgy is mass-produced.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is a homogeneous intermetallic compound//! This invention relates to Ti powder and its manufacturing method.

Aj! Tt alloy has the highest high-temperature strength as a metal material, has high corrosion resistance, and is a lightweight material.

Metaradical transaction (Metalurg)
ical Transaction) Vol, 6A (
1975) P, 1991, it was reported that a high temperature strength of 40 kg/true weight 2 was obtained at 800°C. Therefore, by utilizing these characteristics, I/! Ti alloy is suitable for gas
It is considered suitable for application to tachin parts, automobile engine valves, pistons, high-temperature dies, bearing parts, etc.

(Problems to be Solved by the Invention) AlTi-containing Ti is lightweight, has a high heat resistance, and has high corrosion resistance, so it is suitable for turbine blades used at high temperatures, but it has low ductility at room temperature, so it cannot be rolled or It is difficult to mold by forging, etc., and must be molded using powder metallurgy. For this reason, the conventional method of casting an ingot and pulverizing it has the following problems.

■ Segregation occurs inside the ingot, making it impossible to obtain a homogeneous product.

(2) In the ingot method, AlTi crystal grains become coarse during solidification. 0 Precipitates within and between grains (especially Aj!3Ti
) occurs.

When powdered for powder metallurgy, segregation will result in uneven properties of the sintered product, large grains will prevent the sintered crystal from having sufficient strength, and the presence of precipitates will cause the sintered product to have uneven properties. When a deforming force is applied to a solidified product, cracks occur from this point.

Furthermore, a problem in obtaining powder from an ingot is that it is difficult to grind the ingot into powder and requires a large amount of energy and equipment.

(Means for Solving the Problems) The present invention solves the above-mentioned problems and provides a homogeneous intermetallic compound A/! that makes it possible to obtain good sintered molded products. The present invention provides Ti alloy powder.

Specifically, the present invention provides a homogeneous AlTi powder obtained by pulverizing a flaky solidified material obtained by rapidly cooling an AlTi molten alloy at a cooling rate of 104° C./see or higher in an inert gas atmosphere, and a method for producing the same. be.

According to the present invention, A7 is homogeneous without segregation, has a small grain size, has no precipitates, and is suitable for use in sintering molds! Ti powder can be obtained. The flake-like coagulum produced according to the present invention is thin pieces of 100 μm or less and can be easily pulverized, which solves the difficulty in obtaining powder by pulverizing an ingot.

The present invention will be explained in detail below.

Ajl! and Ti so that the composition is 35-44t%, and 1500-1600% Ti is mixed in an inert gas atmosphere.
Heating and melting to ℃, then lowering and adjusting the temperature to 1400-1500℃. Thereafter, the molten alloy is jetted onto the cooling body from a nozzle provided close to the moving cooling body, and the temperature is increased to 104°C.
By solidifying at a cooling rate of /sec or more to produce AlTi intermetallic compound flakes, and crushing the flakes with a ball mill, the intermetallic compound Aj2Ti for powder metallurgy is produced.
Manufacture powder.

The reason why the composition range of A2 is limited to 35 to 44% is that AJTi intermetallic compound is obtained only within this range, and outside this range, a mixed phase of AlTi and other phases becomes a homogeneous AJ! Ti
This is because it cannot be obtained.

The reason why the cooling rate is 104° C./sec or higher is that a lower cooling rate causes coarsening of crystal grains and generation of precipitates. As a cooling method to achieve a cooling rate of 104° C./sec, a single roll method, a twin roll method, a centrifugal cooling method, etc. can be used. The quenched product has a thickness of approximately 10
It is a flaky coagulum with a size of 0μ intestine and an area of about 20 x 30 squares. The reason for the inert atmosphere is that the raw material A1. This is to prevent Ti from being oxidized. Inert gas is Ar + He, N
! Either of these is fine. The melting temperature is preferably raised to 1500° C. to 1600° C. in order to promote the reaction between AJ and Ti to form an intermetallic compound and obtain a uniform molten state.

The gap between the nozzle and the cooling body may be set to obtain stable flakes, but is preferably 0.1 to 0.4.

The rapidly solidified flakes according to the invention are pulverized by a ball mill.

FIG. 1 schematically shows the apparatus used in the method of the present invention, in which 1 is a crucible for melting the intermetallic compound A/Ti, and at its lower end there is a nozzle 4 that is open facing a cooling body 2 such as a roll. This is provided. The dimensions of the opening of the nozzle 4 are, for example, 0.4 to 0.8 mm in width and 401 mm in length. 3 is a container that houses the crucible and the cooling body and has a protective atmosphere of inert gas inside. 5 is a heating mechanism, 6 is a back pressure setting mechanism for the molten metal in the crucible 1, 7 is a mechanism for charging inert gas into the container 3, and 8 is an exhaust mechanism.

To produce the intermetallic compound AlTi according to the present invention, first, an Al base metal and a titanium sponge are charged into a crucible 1,
The inside of the container 3 is evacuated by the exhaust mechanism 8, and the inert gas is exhausted from the inert gas introduction mechanism 7. Furthermore, the heating mechanism 5
The raw material in the crucible 1 is melted. The melting temperature at this time is 1500 to 1600°C, and after sufficient alloying at this temperature, the temperature is once adjusted to about 1400 to 1500°C. After the adjustment is completed, pressurized gas is introduced into the crucible 1 by the back pressure setting mechanism 6 to apply back pressure and open the opening of the nozzle 4 to transfer the molten alloy in the crucible 1 to a cooling body 2 such as a roll. The flakes are produced by ejecting and rapidly solidifying the flakes, which are then ball milled and powdered.

Example Next, examples of the present invention will be shown.

Aluminum metal and sponge titanium A/ 36wt%
, 50% of Ti was blended to obtain a composition of 64wt% Ti.
0 g was placed in a crucible, heated and melted to 1600°C, and alloyed. Next, once the temperature was adjusted to 1500°C, the molten alloy was heated to a diameter of 0.0 °C by applying a back pressure of 0.3 atm through a nozzle with an opening of 0.6 mm width and 40 mm length. The mixture was jetted onto the surface of a roll with a width of 80 m and solidified to produce quenched flakes with a thickness of 100 μm. The flaky quenched pieces were pulverized for 24 hours using a hard glass ball mill (mixture of ball diameters of 15 φ and 20 φ) to obtain powder with a particle size of 100 μI or less. The composition of the resulting flaky coagulum remained almost the same throughout the entire quenching period.

Furthermore, Table 1 shows the results of investigating the crystal grain size and precipitates of the flaky coagulum. For comparison, the ingot method is also shown.

Table 1 The flake-like coagulated material according to the present invention was completely turned into powder with a size of 100 μm or less after 24 hours of ball mill processing, but small lumps coarsely crushed to 3 to 10 mm from the ingot were processed using a ball mill for 24 hours.
Even after the time treatment, almost no powder was formed.

(Effects of the Invention) As explained above, according to the present invention, the following effects are achieved.

(1) By using the quenching method of the present invention, the flake-like quenched pieces obtained do not contain precipitates, have extremely little segregation, and have a fine crystal grain size of 1 to 3n. The resulting powder has properties that are extremely suitable as a raw material for powder metallurgy.

(2) The quenched pieces obtained according to the present invention are flaky flakes, which can be easily crushed.

Therefore, unlike the case of pulverizing ordinary lumps, it is possible to significantly reduce the pulverizing energy and the burden on the pulverizing equipment, etc., and to homogeneously and inexpensively mass-produce powder for powder metallurgy of the intermetallic compound Al1Ti. Extremely effective.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of an apparatus for implementing the present invention. 1... Crucible, 2... Cooling body, 3... Container, 4...
... Nozzle, 5... Heating mechanism, 6... Back pressure setting mechanism, 7... Inert gas introduction mechanism, 8... Exhaust mechanism. Procedural amendment (spontaneous) June 7, 1985 Michi Uga, Director General of the Patent Office, B. 1, Indication of the case, Patent Application No. 100232, filed in 1988, 2. Name of the invention: Intermetallic compound A/Tl powder and method for producing the same. 3. Relationship with the case of the person making the amendment Patent applicant representative Takeshi 1) Yutaka 4, agent 〒100 6. Column 7 for detailed explanation of the invention in the specification to be amended, contents of the amendment

Claims (2)

[Claims] (1) Crystal grains with a composition range of 35 to 44 wt% of Al obtained by crushing flakes produced by cooling from a molten state at a cooling rate of 10^4°C/sec or more are small;
Intermetallic compound AlTi powder with little precipitates and segregation. (2) 35 to 44 wt% Al and the balance Ti are heated and melted in an inert atmosphere, the molten alloy is jetted onto a moving cooling body, and rapidly solidified at a cooling rate of 10^4°C/sec or more to form flakes. A method for producing an intermetallic compound AlTi powder having small crystal grains and less precipitates and segregation, the method comprising obtaining a solidified product and pulverizing the solidified product.