US2204567A - Magnesium alloy of high strength - Google Patents

Description

Patented June 18,1940

MAGNESIUM ALLoY Arthur Burkhardt,

OF HIGH STRENGTH Berlin-Lichterlelde, and

Richard Knabe,- Berlin-Zehlendori, Germany,

assignors to Georg Breslau, Germany, a

No Drawing.

Application September Von Giesches Erhen, corporation of Germany fe' izal No. 228,322. In Germany September 21,

3 Claims.

Our invention relates to magnesium alloys, andmore particularly to alloys of the class containing aluminium and bismuth.

It is an object ofour'invention to improve a 5 magnesium alloy of the class aforesaid, with a view to increasing its strength.

In the known alloys of this class, the content of bismuth never was made higher than 2%, since experts believed that no improvement would be m attained by increasing the percentage of bismuth. The strength of such alloys was so poor that they never were adopted.

We have made the surprising discovery that the strength of alloys of the class referred to is much increased by. a content of more than 2 up to 14% bismuth, with 0.05 to 8% aluminium. "Our novel alloys, in heat treated condition, possess tensile strengths of the order of 40 kilogrammes per square millimeter, and elongations of 3 to 5%. Such strengths have never been attained heretofore in alloys of this class. Our novel alloys, on account of their favorable mechanical properties, are suitable for purposes such as vehicle and airplane construction where low weight and high strength are important.

The remainder of the alloys may be substantially all magnesium. The phrase all magnesium and magnesium with the usual impurities and minor amounts of alloying elements, generally not more than 0.1 to 1%, as are common in technical magnesium. Such elements are, for in stance, calcium which is known to improve the castability of alloys of the class described; manganese which increases the corrosion resistance; or at least one metal of the iron group, or silicon; for increasing the yield point of the alloys, and their strength under high temperature condisubstantially 3 is intended to include magnesium tions. Such, and other, alloying elements are usual in magnesium alloys, and they do not in any way influence the properties of our novel alloys.

Examples of suitable alloys according to our invention will appear from the following table.

"In worked and heat treated condition.

It is understood that in all cases the remainder is substantially all magnesium.

We claim:

1. A magnesium alloy containing from 0.05 to 8 per cent of aluminium and substantially more than 2 per cent up to 14 per cent of bismuth, the remainder being substantially all magnesium.

2. A magnesium alloy containing from about 5 per cent to about 8 percent of aluminium and. from about 4 per cent to about 8 per cent of bismuth, the remainder substantially all magnesium.

3. A magnesium alloy containing aluminium in an amount between 0.05 and 8 per cent, and bismuth in an amount higher than that of aluminium and being substantially more than 2 per cent up to 14 per cent, the remainder substantially all magnesium.

ARTHUR BURKHARDT. RICHARD IQN'ABE.