JPH06328270A - Magnesium-aluminum clad material and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a clad extruded material cladding an aluminum having good corrosive resistance to a magnesium alloy having bad corrosive resistance. CONSTITUTION:In order to manufacture the clad material consisting of the magnesium alloy as the inner core material and the aluminun or this alloy as the surface layer material, a billet closely coating the surface layer of the magnesium alloy billet with the aluminum or this alloy is heated at <=400 deg.C and the extrusion work is applied to manufacture the clad material. By this method, the corrosive resistance is given with the cladding to the magnesium alloy having the highest specific strength among the practical alloys and the use in lightening is enlarged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clad material of aluminum or its alloy and magnesium alloy, which are materials of light alloys.

[0002]

2. Description of the Related Art In a clad material of light metals, for example, aluminum, it is a well-known technique to clad an aluminum alloy having a high strength with an outer layer of an aluminum alloy having a high strength. Since this is a clad made of the same material, it is easy to manufacture. However, even if it is said that the same kind of material, the clad of magnesium is not performed, let alone the clad of magnesium with a different alloy. When magnesium and aluminum are joined together, an intermetallic compound of Mg ₁₇ Al ₁₂ is formed, but this has a very brittle property, and a stable joint structure cannot be formed, so a magnesium-aluminum clad material has not been conventionally considered.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to magnesium and its alloys, which are lightweight and have high strength, but have limited applications due to poor corrosion resistance.
In order to expand the applications while taking advantage of its advantages, it is an object to develop a clad material using magnesium and its alloy as a base material and to manufacture a clad extruded material having a stable joint structure.

[0004]

According to the present invention, (1) a clad material having a magnesium alloy as an inner core material and aluminum or its alloy as a surface layer material, and (2) a surface layer of a magnesium alloy billet as aluminum or its alloy material. The gist is a method for producing a magnesium-aluminum clad material in which a billet coated by intimate mechanical contact with the above is heated to 400 ° C. or lower and extruded.

The present invention will be described in detail below. In the present invention, magnesium and its alloy as a core material occupy a majority or most volumetrically in order to make the most of the light weight and specific strength of magnesium. Also, aluminum is
In order to make the most of its corrosion resistance, the entire surface except the cut surface or at least one surface of the pipe material is covered.

As a method for producing the clad material billet, a method known for aluminum extruded material may be adopted. The surface of a billet of a magnesium alloy cylinder or prism is processed into a core material, and a precisely machined cylinder of aluminum or its alloy or a cylinder with a bottom is shrink-fitted, or a plate of aluminum or its alloy Cover the front and sides of the billet by ironing. Further, the aluminum surfaces are welded to each other with a plate material to shield the joint surface from the atmosphere.

It is known to extrude magnesium or aluminum at a temperature of about 400.degree. However, it has been found that it is necessary to keep the heating temperature at 400 ° C. or lower in order to carry out the present invention. As is well known, the inventors of the present invention generate a liquid phase at a eutectic point of 437 ° C. of magnesium and Mg ₁₇ Al _{12 when} a magnesium alloy and an aluminum alloy are brought into intimate contact with each other and heated. It has been found that a liquid phase appears with an alloy containing a large amount of heat even after heating at 420 ° C. for a long time. Mg ₁₇ A thus produced
l ₁₂ is very brittle and cracks so as to cleave. Therefore,
It is necessary to suppress the upper limit to about 400 ° C. in consideration of heating error. Also, solution treatment after processing should be avoided. However, artificial aging does not pose a problem because the temperature is low.

[0008] General processing of magnesium alloys is possible from 200 ° C, but in extrusion processing it is safe to keep the lower limit at about 275 ° C to prevent cracks and scratches. For many magnesium alloys, there are aluminium alloys having similar material characteristics and workability, so if they are properly combined, processing is easy, and the material does not deviate from the core magnesium alloy.

As such a clad material, it is desirable to be able to produce a plate material or the like, but it has been difficult to produce materials other than extruded materials in the past. One of the reasons for this is that when rolling the plate, the temperature of the rolling ingot is lowered at 400 ° C., and the working may be difficult in the finishing stage. Also, since there is an oxide between the aluminum and magnesium layers,
Bonding is likely to be insufficient in the rolling of plate materials. On the other hand, since the degree of processing is high in the extrusion processing, the oxides between the layers are completely dispersed.

An aluminum coating is provided on the part of the product which requires corrosion resistance, but the aluminum layer has a minimum thickness of 0.0.
If it is about 5 mm, it has durability for a sufficient period. Since aluminum and magnesium come into contact with the end surface and are exposed on the surface, it is easily subjected to electrolytic corrosion. Therefore, an epoxy resin coating or the like may be performed if necessary.

[0011]

EXAMPLES The present invention will be further described below based on examples. Example 1 (Manufacture of Extruded Pipe Material) A cast ingot of magnesium alloy ZK60 containing 5.38% zinc and 0.52% zirconium as main components was subjected to full-surface cutting to form a cylinder having a diameter of 77.6 mmφ × 198.8 mm. Degrease and wash. On the other hand, 1. of aluminum alloy 5052 containing 2.38% magnesium and 0.28% chromium.
With a 2 mm plate, a bottomed cylinder having an inner diameter of 77.6 mmφ × 198.8 mm is manufactured. Then, the aluminum cylinder was shrink-fitted to manufacture a material. Then, the center was perforated, heated to 400 ° C. in an inert gas heating furnace, and extruded at a die temperature of 400 ° C. to manufacture a tubular material having an outer diameter of 40 mmφ and a thickness of 2 mm.

The aluminum portion of the surface layer of this pipe material was about 0.
1mm, specific gravity is about 1.89, and the material of the whole is Z
The outer surface of the pipe is corrosion resistant due to the high tensile strength material having the characteristics of K60 and the thin aluminum surface layer. Also, 150
Further strength can be exhibited by aging near ℃.

Example 2 (Manufacture of Extruded Mold Material) A magnesium alloy ingot of AZ31 alloy containing 3.12% aluminum, 0.98% zinc and 0.18% manganese as main components was entirely cut to obtain 77.6 mmφ × 19
Finish into an 8.8 mm cylinder and degrease and wash it. Then, using a 1.2 mm thick plate of aluminum alloy 3003 containing 1.2% of manganese which has been annealed in advance,
A 7.6 mmφ cylinder was manufactured. Shrink this into a magnesium alloy ingot. Then, using the same 80 mmφ disc having a thickness of 0.6 mm, both ends of the aluminum part are welded all around.

The ingot whose entire circumference is covered is heated to 380 ° C. in a heating furnace and extruded at a die temperature of 380 ° C.
T-shaped steel with a wall thickness of 2 mm was used. This type steel has a specific gravity of about 1.
84, the aluminum alloy layer thickness is 0.1 mm, the material is AZ31, and it is a clad material of aluminum alloy 3003 having good corrosion resistance.

[0015]

INDUSTRIAL APPLICABILITY The present invention provides a clad material by coating aluminum on the surface of a magnesium alloy having the highest specific strength among practical alloys but having poor corrosion resistance.
It is designed to be used without losing the advantage of its specific strength, is used as a structural material for various transportation equipment, and has an extremely great effect on weight reduction.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Tanahashi 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Inside Nippon Steel Corporation Advanced Technology Research Laboratories

Claims (2)

[Claims] 1. A magnesium-aluminum clad material comprising a magnesium alloy as an inner core material and aluminum or an alloy thereof as a surface material. 2. A method for producing a magnesium-aluminum clad material, which comprises heating a billet obtained by coating the surface layer of a magnesium alloy billet with aluminum or its alloy material by intimate mechanical contact and heating the billet to 400 ° C. or lower and extruding. .