JP3218949B2 - Manufacturing method of powder injection molded Al alloy member with high strength - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention has a high strength,
For example, the present invention relates to a method of manufacturing an Al alloy member suitable for use as a structural member of an automobile part or various electric / electronic devices by a powder injection molding method.

[0002]

2. Description of the Related Art Conventionally, as described in, for example, JP-A-6-304733, a method of manufacturing a structural member made of a low melting point metal such as Pb or Sn by a powder injection molding method is known. This powder injection molding method is shown in FIG.
As shown in the schematic vertical sectional view of the operation process of the powder injection molding apparatus in (c), first, the mold 1 is closed to the state shown in FIG. The raw material powder 10 composed of the melting metal powder is used for the screw plunger 4.
1 is sequentially supplied to the gap between the outer surface of the screw cylinder and the inner surface of the heating cylinder 3 when the screw plunger retreats, and is in a molten and semi-molten state by the band heater 9, which is shown in FIG. The piston 6 of the hydraulic cylinder 7 is driven as described above, and the screw plunger 4 integral with the piston 6 is advanced to inject the molten low-melting-point metal into the mold 1 from the nozzle 2 at the tip of the heating cylinder 3 and pull it. Subsequently, as shown in FIG. 1C, the mold 1 is opened to remove the molded member 11, and the screw plunger is retracted while being rotated by a motor attached to the rear end of the screw plunger. The low melting point metal member is manufactured by repeating the process of supplying the raw material powder 10 from the hopper 5 into the heating cylinder 3 by the retreat of the screw plunger 4. It is a method.

[0003]

However, when an Al alloy member is manufactured using the above-mentioned conventional powder injection molding method, the Al alloy as a raw material powder is injected into a mold in a molten or semi-molten state. However, under such conditions, the Al alloy has a remarkable growth of crystal grains, and at present, the strength of the formed Al alloy member is low.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoints, as a result of conducting research to produce an Al alloy member having high strength using the above-described powder injection molding method, A having an amorphous structure as a raw material powder was obtained.
1 alloy powder or an Al alloy powder having a fine grain structure with an average grain size of 1 μm or less, and injection molding these raw material powders in a superplastic deformation state or a viscous flow state. Since it does not result in molding in a molten or semi-molten state where significant growth of grains is inevitable,
The research results show that it will have high strength.

The present invention has been made on the basis of the above research results, and as the raw material powder, an Al alloy powder having an amorphous structure or an Al alloy powder having a fine grain structure having an average particle diameter of 1 μm or less. Instead of injection molding these raw material powders in a molten or semi-molten state, injection molding is performed in a superplastic deformation state or a viscous flow state indicated by the amorphous structure, or in a superplastic deformation state indicated by the fine grain structure. Thus, the present invention is characterized by a method of manufacturing an Al alloy member having high strength.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the method of the present invention will be specifically described with reference to embodiments. Example 1 As a raw material powder, an average particle diameter of 20 μm was obtained by a nitrogen gas atomizing method, and in% by weight (% by mass) [% indicates% by mass (% by mass)], Al-14% Ni-10% Y
Is charged into the hopper 5 of the powder injection molding apparatus shown in FIG. 1 and transferred to the tip of the heating cylinder 3 by the screw plunger 4. With band heater 9
To 350 ° C. by viscous flow deformation.
It is injected into the mold 1 heated to 00 ° C. from the nozzle 2 having a diameter of 3 mm with a screw plunger 4 at a pressure of 4 ton / cm ² , and has a parallel part dimension of thickness: 5 mm × width: 10 mm × length: 30 mm. Length with: A consisting of a 60 mm tensile test piece
The method A of the present invention was carried out by molding a 1 alloy member.

Example 2 The raw material powder had an average particle size of 20 μm by a nitrogen gas atomizing method, and the powder base material had an average crystal particle size of 0.8 μm.
And a fine grain structure of Al-20% Si-3% C
An Al alloy powder having a composition of u-1% Mg-0.5% Zr was used, and the heating temperature at the tip of the heating cylinder 3 was set to 50 by the powder injection molding apparatus also shown in FIG.
The temperature was set to 0 ° C., and was injected into the mold 1 heated to 300 ° C. with a screw plunger 4 at a pressure of 4 ton / cm ² using superplastic deformation, and had the same dimensions as those manufactured in Example 1 above. The method B of the present invention was carried out by forming an Al alloy member composed of a tensile test piece. Further, for the purpose of comparison, the comparative method B was performed under the same conditions except that the heating temperature at the tip of the heating cylinder 3 was set to 600 ° C. to be in a semi-molten state, and the mold was heated to 350 ° C.

Example 3 A raw material powder having an average particle size of 20 μm and an amorphous structure by a nitrogen gas atomizing method,
An Al alloy powder having a composition of 4% Ni-10% Y was prepared. Further, as a powder injection molding apparatus, a transfer molding and solidifying apparatus having a structure shown in a schematic longitudinal sectional view in FIG. 2 was prepared. First, the Al alloy powder is charged into the powder quantitative feeder 12 shown in FIG. 2, and a predetermined amount of the Al alloy powder 13 is sent to an atmosphere gas fluidized bed heating furnace 14 through a screw transfer device, where it is heated to 550 ° C. Is filled in a transfer pot 16 formed in the upper mold of the mold 15, and the plunger 17 is heated to 300 ° C. by utilizing crystallization-superplastic deformation caused by heating to a temperature higher than the crystallization temperature. The method C of the present invention is carried out by injecting a 4 ton / cm ² pressure into the cavity 18 formed in the lower die and forming an Al alloy member consisting of a tensile test piece having the same dimensions as those manufactured in Example 1 above. Was carried out. For the purpose of comparison, the heating temperature of the Al alloy powder in the transfer pot 16 was set to 6
50 ° C to make a semi-molten state and mold temperature 400 ° C
Comparative method C was performed under the same conditions except that

[0009] With regard to the Al alloy member obtained as a result,
A tensile test was performed and the results shown in the table below were obtained. The following table also shows the theoretical density ratio.

[0010]

According to the results shown in the above table, the methods A to A of the present invention can be used.
According to C, it is clear that an Al alloy member with higher strength can be manufactured as compared with the comparative methods B and C in which injection molding is performed in a semi-molten state. As described above, in the method of the present invention, injection molding is not performed in a molten or semi-molten state, but in a superplastic deformation or viscous flow state indicated by an amorphous structure, and further, an average particle diameter is 1 μm.
Injection molding is performed in a superplastic deformation state indicated by a fine crystal grain structure of m or less, so that the crystal grains become fine, thereby enabling Al alloy members having high strength to be formed, and miniaturization and thinning of various structural members. It also contributes to the development.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an operation process of a powder injection molding apparatus.

FIG. 2 is a schematic longitudinal sectional view of a transfer molding and solidifying device, which is one type of powder injection molding device.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Kono 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Materials Corporation General Research Laboratory (56) References JP-A-63-203735 (JP, A) 2-70046 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 17/00 B22D 21/04 B22F 1/00 B22F 3/14 C22C 1/04

Claims (1)

(57) [Claims] 1. An aluminum alloy powder having an amorphous structure or an aluminum alloy powder having a fine crystal grain structure having an average particle diameter of 1 μm or less is used as a raw material powder, and these raw material powders are injection-molded in a molten or semi-molten state. Rather than performing injection molding in a superplastic deformation state or viscous flow state indicated by the amorphous structure, or in a superplastic deformation state indicated by the fine grain structure, a powder injection-molded Al alloy member having high strength, Manufacturing method.