JP3137911B2 - Composite materials for extrusion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite material having excellent processing characteristics at the time of extrusion processing using an oxide ceramic as a reinforcing material.

[0002]

2. Description of the Related Art Among metal-based composite materials, especially when the reinforcing material is ceramics, it exhibits excellent properties such as abrasion resistance, heat resistance and strength, and furthermore, a light metal alloy such as Al or Mg is used as a matrix metal. When used, the material can be reduced in weight, and thus can be said to be a suitable material for automobile parts and the like. And such a composite material is usually produced by a pressure casting method, for example, by keeping a matrix metal just above a melting point, and producing by a squeeze casting method such as applying a pressure to composite. Like that.

[0003]

However, when the above-described extrusion processing is performed on the composite material, cracks are liable to occur. Particularly, when the volume content (Vf) of the reinforcing material is 10% or more, extrusion becomes impossible. However, there is a problem that it is difficult to use industrially. That is, as shown in FIG. 2A, the composite material obtained by the above-described pressure casting method includes alumina (Al ₂ O ₃ ) as a reinforcing material and aluminum (Al) as a matrix metal (base material). In the state of a mechanical contact that is simply mechanically connected, when a large plastic deformation occurs in the matrix metal (Al) by extrusion, the reinforcing material (A)
Large buckling stress is generated at the interface between (l ₂ O ₃ ) and the matrix (Al), and peeling or displacement of the interface occurs as shown in FIG. However, this is a factor that frequently causes scabs and the like.

[0004] Therefore, a technique for extruding a composite material of a ceramic reinforced material having such excellent properties as wear resistance, heat resistance and strength into pipes and rods without impairing the excellent properties. Is desired.

[0005]

In order to solve the above-mentioned problems, an extrusion composite material according to the present invention is characterized in that at least the surface layer of a reinforcing material of an oxide-based ceramic such as fibrous, whisker-like or particulate is reduced to reduce at least the surface layer portion. The metal was partially exposed, and subsequently an alloy base material such as aluminum or magnesium was compounded in an inert atmosphere, and then cooled and solidified under a pressurized atmosphere.

Here, if the surface layer of an oxide ceramic such as alumina (Al ₂ O ₃ ) is reduced to expose a metal such as aluminum (Al) to form a composite, the wettability between the exposed metal and the matrix metal is reduced. As a result, the composite is easily formed, and at the same time, the interface becomes a chemical contact state in which it is chemically bonded in a state of being micro-clad, so that the interface is firmly bonded.

Further, by cooling and solidifying in a pressurized atmosphere, the bonding strength between the reinforcing material and the matrix metal is improved, and even if the matrix metal is deformed during extrusion, the interface between the reinforcing material and the matrix metal is peeled off and shifted. Etc. are less likely to occur and exhibit good processing characteristics.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory view of an interface between a reinforcing material of a composite material and a matrix metal according to the present invention, FIG. 2 is an explanatory view of an interface between a reinforcing material of a conventional composite material and a matrix metal, and FIG. FIG. 4 is a completed view of an automobile engine sleeve formed of the composite material according to the present invention.

The composite material for extrusion according to the present invention is, for example, shown in FIG.
It is suitable for extruding a part requiring characteristics such as wear resistance and heat resistance, such as an automobile engine sleeve S shown in FIG. It is characterized in that it can be processed well even with a composite material having a content (Vf). The composite material for extrusion is manufactured by the following molding method.

That is, in a composite material in which a light metal alloy such as aluminum or magnesium is compounded as a matrix metal with a reinforcing material of oxide ceramics such as fibrous, whisker-like, or particles, at the stage of compounding, The surface layer is subjected to a reduction reaction to expose the metal to at least a part of the surface layer. The reduction of the surface layer portion of the reinforcing material is performed using, for example, a reducing agent and is performed under an inert atmosphere.

Then, while maintaining the inert atmosphere state continuously while the metal is exposed, it is combined with a light metal alloy such as aluminum or magnesium as a matrix metal, and cooled and solidified under a pressurized atmosphere. In addition, the exposed metal is in an activated state, the wettability with the matrix metal is improved, the composite is quickly formed, and the degree of bonding between the reinforcing material and the matrix metal is increased.

Here, when the reinforcing material is alumina (Al ₂ O ₃ ) and the matrix metal (base material) is aluminum (Al), the surface layer of alumina (Al ₂ O ₃ ) is formed as shown in FIG. )
As shown in (2), a reduced aluminum layer is formed to be in a chemical contact state, and is firmly bonded.

Next, when forming an extruded product from the composite material, for example, an extrusion die 1 as shown in FIG.
Extrusion processing. Then, the matrix metal (Al) undergoes large plastic deformation due to this extrusion, but the bonding state between the reinforcing material (Al ₂ O ₃ ) and the matrix (Al) is strong, so that the bonding is performed as shown in FIG. The state is maintained, and no peeling or the like occurs. Therefore, problems such as cracking of the composite material and galling of the mold are suppressed. By the way,
FIG. 2 shows an example of forming a sleeve for an automobile engine. The extruded product formed as shown in FIG. 3 (B) by such an extrusion process is subjected to an end face processing and formed into a sleeve S as shown in FIG. Is done.

(Examples and Comparative Examples) Next, a method of manufacturing a composite material for extrusion according to the present invention and an example in which the sleeve for an automobile engine is extruded using the composite material will be described. The results are shown in comparison with the case where the composite material was extruded by using the composite material. First, an inert atmosphere (A
r) in the Al ₂ O ₃ fiber (trade name Safir (I
CI)), 3% of magnesium nitride (Mg ₂ N ₃ ) powder was added as a reducing agent to the assembly, and the temperature was raised to 800 ° C.

In this operation, the surface layer of the Al ₂ O ₃ fiber was converted to Al by a reduction reaction and activated. Thereafter, while continuously maintaining an inert atmosphere, a molten aluminum of the A6061 alloy was poured into the assembly, and then cooled and solidified in a pressurized atmosphere to form a composite. According to such a method, Al ₂ O ₃ / Al having a volume content (Vf) of 5%, 10%, or 15%
A composite material was manufactured, and an extruded billet B having an outer diameter of １４145, an inner diameter of ８７87 and a height of 95 mm was processed from the composite material.

Next, this extruded billet B is inserted into the billet B shown in FIG.
In a state as shown in (A), it was set in a mold and extruded under extrusion conditions as shown in the following (Table 1). As a comparative example, an Al ₂ O ₃ / Al composite material was manufactured by a conventional squeeze casting method, and an extruded billet B having the same form as that of the example was extruded.

[0017]

[Table 1]

By this extrusion process, FIG.
As shown in (B), the result of extruding a sleeve for an automobile engine having an outer diameter of φ92 and an inner diameter of φ85 and examining the occurrence of cracks in the composite material during processing and the occurrence of galling on the mold is as follows. (Table 2). As a result, it was proved that the processing characteristics at the time of extrusion were good in any case where the volume content (Vf) was 5%, 10% or 15%.

[0019]

[Table 2]

In addition, various kinds of composite materials are 35 × 150 × 5 mm
After heating to 300 ° C., a heat shock test in which a cycle of rapid cooling by water cooling was repeated 10 times was performed. The results are as shown in the following (Table 3). While the conventional composite materials all cracked and cracked, the composite material according to the present invention after the extrusion process showed cracks. And no cracks were observed. Further, in the composite material according to the present invention, before the extrusion process, slight cracks were observed.

[0021]

[Table 3]

Incidentally, the volume content Vf of the reinforcing material is 15
%, The material properties of the composite material are as shown in the following (Table 4). In particular, the strength and elongation after extrusion are improved as compared with those before extrusion, and it can be seen that the mechanical properties are excellent. .

[0023]

[Table 4]

From the above, the composite material according to the present invention and the processed product extruded using the composite material are required to have abrasion resistance, heat resistance, and high strength such as a sleeve for an automobile engine. It is suitable to be applied to such components, and has high industrial utility value.

In the embodiment, the fiber has been described as an example of the oxide-based ceramic reinforcing material. However, other materials such as whiskers and particles may be used, and the matrix metal may be made of Mg other than aluminum (Al). Or other light metal. Further, the extruded product is not limited to a sleeve for an automobile engine.

[0026]

As described above, the composite material for extrusion of the present invention can be extruded while making use of the inherent high strength, wear resistance and heat resistance of the composite material using oxide ceramics as a reinforcing material. An extruded product formed from the composite material can be freely processed into a pipe, a rod, or the like by processing, and has excellent mechanical properties, so that it can be widely used in industry.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an interface state between a reinforcing material of a composite material according to the present invention and a matrix metal.

FIG. 2 is an explanatory diagram of an interface state between a reinforcing material of a conventional composite material and a matrix metal.

FIGS. 3A and 3B are explanatory views illustrating an extrusion molding state, in which (A) is before processing and (B) is after processing.

FIG. 4 is a completed view of an automobile engine sleeve formed from the composite material according to the present invention.

[Explanation of symbols]

 1. Mold, B ... billet, S ... sleeve.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI C22C 47/02 C22C 1/09 A 47/08 F (72) Inventor Tadashi Kobayashi 1-1-10 Shinsayama 1-chome, Sayama-shi, Saitama (58) Field surveyed (Int.Cl. ⁷ , DB name) B21C 23/00-35/06 B22D 19 / 00,19 / 14 B22D 23 / 00,27 / 09 C22C 47/02, 47 / 06,47 / 08

Claims (1)

(57) [Claims] 1. A method for reducing a surface layer of a reinforcing material of an oxide-based ceramic, such as fibrous, whisker-like, or particulate, to expose at least a portion of a metal, and continuously exposing the aluminum in an inert atmosphere in an inert atmosphere. Alternatively, a composite material for extrusion, which is obtained by compounding an alloy base material of magnesium or the like, and further cooling and solidifying the mixture in a pressurized atmosphere.