US1975120A

US1975120A - Alloy

Info

Publication number: US1975120A
Application number: US705285A
Authority: US
Inventors: Roy E Paine
Original assignee: MAGNESIUM DEV CORP
Current assignee: MAGNESIUM DEV CORP; MAGNESIUM DEVELOPMENT Corp
Priority date: 1934-01-04
Filing date: 1934-01-04
Publication date: 1934-10-02
Anticipated expiration: 1951-10-02

Description

Patented Oct. 2, 1934 UNITED STATES PATENT OFFICE mesne assignments, to Magnesium Development Corporation, a corporation of Delaware No Drawing. Application January 4, 1934, Serial No. 705,285

2 Claims.

The invention relates to magnesium base alloys. An object of the invention is the development of alloys of this nature containing tin and cobalt.

I have discovered that when cobalt is added to magnesium base alloys containing tin, the resulting alloys undergo an improvement in both tensile strength and elongation. I have also discovered that the magnesium-tin-cobalt alloys may be further improved by suitable thermal treatments.

As an illustration of the effect produced by the addition of cobalt to a magnesium base alloy, 1,.

have made up an alloy of this nature containing 5.0 per cent of tin, the balance being commercial magnesium. This alloy had a tensile strength, in the cast condition, of 18,380 pounds per square inch and an elongation of 5.0 per cent in two inches. A second alloy containing, in addition to 5.0 per cent of tin, 0.5 per cent of cobalt had in the cast condition a tensile strength of 18,940 pounds per square inch and an elongation of 5.7 per cent in two inches. A third alloy containing 2.0 per cent ofcobalt, in addition to 5.0 per cent of tin, had in the cast condition a tensile strength of 20,920 pounds per square inch and an elongation of 6.3 per cent in two inches. It may be observed that the above additions of cobalt have successively increased both strength and elongation.

A thermal treatment of 19 hours at 525 centigrade followed by quenching increased the strength of the 0.5 per cent cobalt alloy from 18,940 pounds to 23,680 pounds per square inch and the elongation from 5.7 per cent to 8.8 per cent in two inches. After the same thermal treatment the tensile strength of the-2.0 per cent cobalt alloy increased from 20,920 pounds to 24,670 pounds per square inch and the elongation increased from 6.3 per cent to 9.2 per cent in two inches.

Another magnesium-tin alloy containing 10.0 per cent -of tin, the balance being commercial magnesium, was made up tocontain, in addition,

1.0 per cent of cobalt. This alloy on being heated for 19 hours at 525 centigrade and quenched had a tensile strength of 23,220 pounds per square inch and an elongation .of 7.8 percent in two inches. After an additional aging treatment of 20 hours at 150 centigrade the tensile strength C9 increased to 26,750 pounds per square inch and the elongation to 9.8 per cent in two inches. In alloys of the type herein discussed the cobalt may be present in amount between about 0.1 per cent and 4.0 per cent and may be added to magnesium-tin alloys containing from about 0.1 per cent to about 20.0 per cent of tin. As a preferred composition I have used an alloy containing 5.0 per cent of tin and 1.0 per cent of cobalt, the balance being commercial magnesium.

The alloys are susceptible to variations in their physical properties by thermal treatments at temperatures most effective between about 425 and 525 centigrade and may be given additional aging treatments between about 100 and 200 centigrade. They may be compounded in any of the ways familiar to the art, such as by adding to the molten magnesium bath the alloying element when its melting point is below that of the magnesium, or approximates it, or by adding the 8 alloying element in the form of a magnesiumrich alloy or hardener when its melting point considerably exceeds that of the magnesium.

The alloys disclosed herein may be extruded over the whole range disclosed, and may be forged or otherwise mechanically deformed when the amountof added alloying elements does not become too great a proportion of the whole.

In this specification and the appended claims the term magnesium base alloy signifies an alloy containing more than 50 per cent magnesium.

I claim:

1. A magnesium base alloy containing from 0.1 per cent to 20.0 per cent of tin and from 0.1 per cent to 4.0 per cent of cobalt, the balance being substantially all magnesium.

2. A magnesium base alloycontaining about 5.0 per cent of tin and 1.0 per cent of cobalt, the balance being substantially all magnesium.

' f ROY E. PAINE.