US2305825A - Magnesium alloy - Google Patents

Description

MAGNESIUM ALLOY Arthur Burkharclt, Berlin-Lichterfelde, and Karl Riederer, Munich, Germany: vested in the Alien Property Custodian No Drawing. Application November 9, 1939, Se-

rllgl lo. 203,614. In Germany December 23, 1

a 5 Claims. (01.75-168) Our invention relates to magnesium alloys. In our co-pending patent application, Ser. No. 198,691, filed March 29, 1938, we have described a heat-treatable magnesium alloy containing 1 of the four metals bismuth, cadmium, lead, and

zinc is particularly favorable technologically.

According to the present invention, alloys of the kind referred to contain 1 to 14% aluminium and 0.5 to 10% of each of the said four metals, and the percentages of the four metals are so determined that the metals together make up about 3 to 23% of the alloy, and preferably 4 to 14%. The remainder in these and in all other alloys embodying our invention that will be described. is substantially all magnesium. The phrase substantially all magnesium is intended to include magnesium and magnesium with minor amounts of customary impurities and auxiliaries. Such auxiliary alloying elements are, for instance, 0.1 to 2% each oi manganese, calcium, silicon, or 0.2 to 4% titanium, or 0.02 to 3% lithium, or one of the metals of the iron group (iron, nickel or cobalt) separately or collectively. Such and other auxiliaries are usual in ma nesium alloys and they do not influence the characteristic properties of our novel alloys.

In a preferred embodiment of our invention, the composition is as follows: 5 to 7% aluminium, 0.5 to 3% bismuth, 2 to cadmium, 2 to 4% lead, and 1 to 3% zinc, remainder substantially all magnesium, with, for instance, 0.5% man ganese for improving the corrosion resistance of the alloy.

This alloy, when, by way of example, used for castings. shows excellent castability, surprisingly dense structure and satisfactory strength at elevated temperatures. The mechanical properties are excellent. In cast and heat treated condition, the alloy has a tensile strength of 27 to 30 kg. per sq. mm. and 0 to elongation.

It is within the scope of our invention to replace cadmium, lead, and zinc wholly or partly by thallium and/or tin. The additions of about 0.2 to 4% titanium and/or about 0.02 to 3% lithium, as mentioned, have a favorable influence on the heat treatability of our novel alloys. and, by way of example, the hardness can be increased for 50% or more. a

In conclusion, our novel alloys may contain: 1

to 14% aluminium, and 0.5 to 10% of each of the metals bismuth, cadmium, lead, and zinc. The four metals-are so proportioned as to make up 3 to 23% of the alloy, preferably 4 to 14%. If desired, 0.2 to 4% titanium, and/or 0.02 to 3% lithium may be added. Remainder substantially all magnesium, as defined.

A. modified alloy according to the invention has the following composition: 1 to 14% aluminium, about 0.5 to 10% bismuth, and about 2.5 to 22.5% of metal selected from cadmium, lead, zinc, thallium and tin, the content 01' bismuth and the selected content making up to gether 3 to 23% of the alloy. Remainder substantially all magnesium.

Another modified alloy according to the invention ls'as follows: 1 to 14% aluminium, about 0.5 to 10% bismuth, and about 3.5 to 13.5% of metal selected from cadmium, lead, zinc, thallium, and tin. The content of bismuth and the selected content make up together about 4 to 14% of the alloy, and the remainder is substantially all magnesium, with or without the aforementioned additions of 0.2 to 4% titanium and/or 0.02 to 3% lithium.

In the following tabulation, some more examples of alloys according to our invention are given, it being understood that for all alloys in the tabulation the remainder is substantially all magnesium as defined above, with or without the titanium and lithium additions.

Examples Content oi constituents, per cent No.

A1 Bi Cd Pb Zn Sn Tl Ti Li 1 1 0.5 1 1 1 2. 5 0.5 2 2 l 3. 3 0.8 8 3 2 4- 8 1.5 l 0.5 1 5. 8 3 5 5 7 o. 12 o 2 a 7 7. l2 8 4 5 5 8. 14 1.5 2.5 2 1 9. 6 0.5 1 2 1 1 1o 5 0.5 1 2 1 1 ll 6 0.5 l 2 1 0.5 0.5 l2 5 0.5 2 1 1 1 13.... 5 0.5 2 1 1 l l4... 5 0.5 2 l 1 15.-- 5 0.5 2 2 1 1c-.- 5 0.5 2 2 1 0.5 17..- 5 0.5 2 2 l 3 18..- 6 0.5 2 2 1 1 0.2 19 5 0.5 2 1 1 1 1 20 6 0.5 2 1 1 1 We claim:

1. A light metal alloy containing 1 to 10% aluminum, about 0.5 to 10% bismuth, about 0.5 to 10% cadmium, about 0.5 to 10% lead, about 0.5 to 10% zinc, and a remainder of 63 to 96% consisting substantially all of magnesium, said constituents of the alloy other than magnesium and aluminum forming a total of about 3 to 23%.

2. A light metal alloy containing 5 to 7% aluminum, 0.5 to 3% bismuth, 2 to 4% cadmium, 2 to 4% lead, 1 to 3% zinc, the remainder substantially all magnesium.

3. A light metal alloy containing 1 to 14% aluminum, about 0.5 to 10% bismuth, about 0.5 to 10% cadmium, about 0.5 to 10% lead, about 0.5 to 10% zinc, the total amount of bismuth, 1

selected metal being present in an amount of 0.5 to 10%, and a remainder consisting substantially all of magnesium, the total amount of said constituents other than aluminum and magnesium being about 3 to 23%.

5. A light metal alloy containing 1 to 14% aluminum, 0.5 to 10% zinc, 0.5 to 10% bismuth,

0.5 to 10% cadmium, metal selected from the.

group consisting of lead, tin and thallium, each selected metal being present in an amount of 0.5 to 10%, and a remainder consisting substantially all of magnesium, the total amount of said constituents other than aluminum and magnesium being about 4 to 14%.

ARTHUR BURKHARD'I'. KARL RIEDERER.