US1721768A - Magnesium alloy and method of making same - Google Patents

Description

Patented July 23, 1929.

UNITED STATES PATIENT oFFlcE.

. v L EDWARD C. BUBDICK, OF MIDISAND, MICHIGAN, ASSIGNOR TO THE DOWOHEMICAL COMPANY, OF MIDLAND, MICHIGAN, CORPORATION OF, MICHIGA 1\ T.

MAGNESIUM ALLOY AND METHOD or mama. sAniE.

No Drawing.

The difliculties involved in alloying copper and manganese with magnesium will be found-set forth in U. S. Patent No. 1,334,193 issued to W. R. Yeazey, March 16, 1920. Ac-

5 cording to the method disclosed in this patent the desired amount of copper is first interfused with the magnesium and then the de sired amount of manganese added in the form of anhydrous manganous chl'oride to the copper-magnesium alloy that is thus preliminarily formed. The manganous chloride is reduced to the metal by the excess of magnesium present, as explained in Patent No.

1,377,37d issued to W. R. Veazey, May 10, 1921. l

I have discovered that the alloy contain-'1 ing the three metals in question, in which magnesium is the predominant constituent,

, course be limited, except as other additions be made thereto, to the same relative proportions of copper and manganese as are found in such cupro manganese. However, a ternary alloy of this composition has been found to possess several desirable characteristics.

The invention then consists of the new product, viz, an alloy containing magnesium in predominant amount and a relatively small amount of copper and manganese in approxi- 40 mately the proportions stated, together with the several steps involved in the making of such alloy hereinafter fully described and particularly set forth in the claims.

The following description it will be understood thus sets forth but one of the several ways in which the invention. may be carried out.

The manner which cupro manganese is made, this being a well'known alloy, need not be described herein, it being suflicient to note that the standard composition of this alloy is, as stated-above, 70 per cent copper and 30 per cent manganese. In utilizing this ready to hand material for the'making a a 65 of the desired ternaryfalloy, which Application filed December 9, 1924. .Serial No. 754,856.

nesium is the predominant. ingredient i'. e. is present in substantial excess of one half the total, I first melt a measured'quantity of magnesium in asuitable crucible or melting V a pot, preferably usihga flux of slightly greater specific igravit'y tha'n the molten metal and having s'uflicient surface tensiom to cause it .to form a filmthereoverand thusprevent exposure of the metal to the atmosphere. The cupro manganese is then'added to such molten magnesium, dissolving completely.

and fairly promptly, thorough iiitermixture being'insured" by stirring if necessary;

"The'molten alloymay then be conveniently removedfrioni the crucibleor melting pot '70 by means ofan ordinary ladle and cast into bars or such other shapes as" may 'be desired; While the'tamount of cupro manganese thus added" may "be varied, I" have foundvery satisfactory results are obtained where it is" added-in an amount equal to one per cent of the total mass; Thls will give a resulting alloy in which the copper and manganese will aggregate approximately one per cent of .the total, being. actuallyso slightlyless due'to losses inherent inthe' process. The proportion of the..copper to the manganese will,-howeyer, remain substan tially unchanged. I

Thus, for example, 20 pounds of magnesium may be melted up and grams of cupro manganese added, such addition being calculated to'give an analysis of 0.70 per cent copper, I and 0.30 per cent-of manganese. The actual analysis of the resultant ternary alloy then 90 shows approximately 0.70 per cent'of copper and approximately 0.20'per cent of manganese, indicating that notsall 9f the man-- ganese has remained in the nal alloy. I have been able to obtain by the'foregoing' method a manganese content as high as 0.26 per cent of'manganese. I J

Castings made from the resultant alloy have a very fine grained structure even when the metal is poured very hot in casting. ThlS is a consequential advantage, since with many magnesium alloys the proper pouring temperature has to be ascertained and carefully observed. Test bars made from an alloy having the com osition first given above show an average yie d point of-8240 pounds, and an ultimate strength of 20,200 pounds.

- It will be-understood' that while have specifically described the addition of cu'p'romanganese .to magnesium alone, it may be added to other alloys of the general type in" which magnesium predominates, i. e. large- 1y exceeds one-half of the total. Thus such cupro-manganese may he added to the known 5 alloy of magnesium with aluminum (see United States patent to Pistol, et al. No. 950,290) containing the last named metal in various amounts up to 20 per cent, the specific v illustration given containing 92 per cent magnesium and 8 per cent aluminum.

Othermodesof applying the pr nciple of my invention may be employed instead of the one explained, change being made as regards theeomposition and method herein disclosed, provided the ingredients or steps stated by 20 tinctl'y claim as my invention 1. The method of making a copper-manmamee v ganese-magnesium alloy, which consists in interfusing with magnesium a relatively small amount of cupro-manganese having the copper and manganese present in approximately the ratio of seven to three.

2. Themethod of making a copper-manvganese-magnesium alloy, which consists in melting a quantity of magnesium, and then adding thereto approximately one per cent of cupro-manganese.

3. The i'nethod of making a copper-manganese-magnesium a1l0y, which consists in melting a quantity of magnesium, and then adding thereto approximately one per cent of cupro-manganese wherein the copper and manganese are present in approximately fluratio of seven to three. c Signedby me this 5th day ofDecemln-r, 1924.

EDWARDC. BURDICK.