JPH0941066A - Magnesium alloy capable of cold press working - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a magnesium alloy capable of executing cold pressing by preparing a magnesium alloy contg. a specified amt. of lithium. SOLUTION: A magnesium alloy contg., by weight, 6 to 16% lithium, contg., at need, at least one kind among 0.3 to 5% yttrium, <=4% zinc, <=6% aluminum and silver, manganese, silicon, calcium, zirconium and lanthanoids respectively by <=2%, and the balance magnesium with inevitable impurities is prepd. Thus, the lightweight magnesium alloy high in strength and having cold press workability such as bendability and drawability can be obtd.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to light weight, high strength,
The present invention relates to a magnesium alloy having cold press workability such as bending and drawing, and more specifically to a magnesium alloy which enables cold press work other than punching, which is impossible with conventional magnesium alloys.

[0002]

2. Description of the Related Art Magnesium alloys are attracting attention in the recent trend of weight reduction of materials in automobiles, home appliances and OA industries. Among them, AZ31 (Mg-3 wt% Al-0.7 wt% Zn is generally used for rolled magnesium.
-0.3 wt% Mn) alloy is used, but it is poor in plastic workability at room temperature, and press work such as bending and drawing other than punching work cannot be done unless it is heated to a high temperature of about 300 ° C. Pressing of iron material and aluminum material, which competes with rolled magnesium material, is generally performed without heating. Therefore, the press processing company often does not have a facility for heating the material. That is, the lack of plastic workability of the rolled magnesium material at room temperature has prevented the spread of the rolled magnesium material.

On the other hand, regarding the magnet-lithium alloy,
LA1 for casting by NASA as a super lightweight material in the 1950s
41 (Mg-14 wt% Li-1 wt% Al: specific gravity 1.
4) Alloys have been developed. Also, in the 1990s, L
Superplasticity of rolled material of i7 to 10.5% by weight was found and a patent application has been made (JP-A-6-65668).

However, the superplasticity exhibited at a high temperature is often not linked to the cold press workability. For example, a superplastic alloy of zinc cannot be plastically worked at room temperature. Therefore, the Magne-lithium alloy has not been linked to the solution of the lack of plastic workability of the rolled material.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and is capable of cold press working with press workability such as cold bending and drawing. The purpose is to provide a new magnesium alloy.

[0006]

In order to solve the above problems, the present inventors have examined various conditions for obtaining cold press workability of a rolled material of magnesium-lithium alloy. As a result, they have found that it is effective to contain a specific amount of elements such as lithium. That is, the present invention resides in a cold-pressable magnesium alloy characterized by containing 6 to 16% by weight of lithium and the balance of magnesium and inevitable impurities.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the content of lithium is 6
~ 16% by weight. The lithium content is HCP phase (α
Phase) and BCC (β phase), which is a eutectic of 6% by weight or more, remarkably improves cold workability. This tendency is further improved as the amount of lithium increases, but if it exceeds 16% by weight, the corrosion resistance remarkably decreases and it is not suitable for practical use.

In addition to lithium, the magnesium alloy of the present invention contains 0.3 to 5% by weight of yttrium, 4% by weight or less of zinc, 6% by weight or less of aluminum, silver, manganese, silicon, calcium, zirconium and lanthanoid. It can contain up to 2% by weight of at least one element.

The rolled plate obtained from this magnesium-lithium alloy has cold press workability, but if a third element such as yttrium is added to the rolled plate, workability is further improved and strength is improved at the same time. be able to.

Yttrium has an effect of refining the structure when added in an amount of 0.3% by weight or more, and as a result, improves strength and workability. However, if it exceeds 5% by weight, the effect is saturated. The addition of zinc is effective in improving strength and, at the same time, promotes recovery and recrystallization, thus improving workability as a whole. However, if it exceeds 4% by weight, the material becomes brittle. Aluminum is also extremely effective in improving strength, but is not effective in improving workability like zinc. If it exceeds 6% by weight, the effect is saturated. Similar to aluminum, silver, lanthanoid, silicon, calcium, etc. also have the effect of improving strength. When the content of each exceeds 2% by weight, the effect is saturated or the material becomes brittle. Zirconium and manganese have the effect of refining the structure, and as a result, improve strength and workability. However, it is not possible to add more than 2% by weight of these elements.

The above magnesium alloy of the present invention is used as a rolled material. This rolled material can be obtained, for example, by rolling the above alloy at a temperature of 350 ° C. or lower, and then performing heat treatment at 100 to 300 ° C. for 30 minutes to 6 hours to improve press workability. As described above, the above alloys are generally rolled at a temperature of 350 ° C. or lower, but the existing AZ
It can be easily processed at a lower temperature than 31 alloy. The rolled material thus obtained is used for various pressed parts.

[0012]

EXAMPLES The present invention will be further described below based on examples. Examples 1 to 16 and Comparative Examples 1 to 3 Raw materials were charged and melted in a vacuum melting furnace in an argon atmosphere so that alloys having the compositions shown in Table 1 were obtained. The crucible used cast iron material, and did not use flux or the like. The molten metal was cast into a mold of 50 mm × 50 mm × 300 mm to prepare a test casting.

The casting thus obtained is heat-treated at 350 ° C. for 4 hours, and then at 250 ° C., the thickness is 10 mm to 1 mm.
Then, as shown in Table 1, a test piece was annealed at 150 ° C. for 4 hours or not annealed. The following tests were carried out on these test pieces. All tests were conducted in the rolling direction. In addition, the misch metal (Mm) in the table is mainly composed of Ce 45 wt%, La 22 wt%, Nd 13.5 wt% and Pr 6.3 wt%. The results are shown in Table 1.

<Tensile test> Test piece: thickness 1 mm, length 20 mm, width 20 mm, gauge length 10 mm, gauge interval 5 mm, pulling speed 10 mm / min, 25 ° C. <bending test> specimen: thickness 1 mm , Length 50 mm, width 5 mm, measured at the tip r of the bending jig according to JIS Z2248 standard (V block method), 25 ° C. <Erichsen test> Test piece: thickness 1 mm, length 90 m
m, width 90 mm, according to JIS Z 2246 standard, 2
5 ℃

[0015]

[Table 1]

[0016]

As described above, the magnesium alloy and the rolled material of the present invention can be bent and drawn in a cold state by adding a specific amount of various elements such as lithium or by applying a specific heat treatment. It became possible to press.

The magnesium alloy having cold press workability of the present invention greatly expands the use of the magnesium alloy which could not be conventionally pressed at room temperature. Specifically, it can be widely used for home appliances, office equipment case parts, multimedia equipment cases, mechanical parts, aerospace related parts, and automobile parts.

Claims (5)

[Claims] 1. A cold-pressable magnesium alloy comprising 6 to 16% by weight of lithium and the balance magnesium and inevitable impurities. 2. Lithium 6 to 16% by weight, yttrium 0.3 to 5% by weight, zinc 4% by weight or less, aluminum 6% by weight or less, silver, manganese, silicon, calcium, zirconium and lanthanoid each 2% by weight. A cold-pressable magnesium alloy characterized by comprising at least one of the following elements and the balance magnesium and inevitable impurities. 3. A rolled material made of the magnesium alloy according to claim 1. 4. The magnesium alloy according to claim 1 or 2 is rolled at a temperature of 350 ° C. or lower, and then 100 to 3
A method for producing a rolled material, which comprises performing heat treatment at 00 ° C. for 30 minutes to 6 hours. 5. A pressed part using the rolled material according to claim 3.