US2747991A - Magnesium-base alloys - Google Patents

Description

United States 2,747,991 Patented May 29, 1953 "ice 2 silicon, silver, strontium, tantalum, thallium, tin, tit-anium, vanadium, and zinc.

2,747,991 The new allows of the invention may be prepared by any of the usual melting processes with precautions to MAGNESIUM-BASE ALLOYS 5 prevent an excessive sodium contamination. For ex- Alf d H, H Worthington, Ohi i nr, by em ample, the magnesium may be melted in an iron crucible. assignments, to Olin Mathieson Chemical Corporation, under a suitable flux, and then the beneficial metal or acorporation of Virginia metals are added, followed by the addition of lithium. N0 Drawmg. Apphcatwn September 14, 1945 11 order to avoid excesslve ox1dat1on of the lithium dur serial 616,161 mg the alloying process, 1t is advisable to use means for holding thehghtweight hthlum beneath the surface of 1 Claimthe molten metal. An inverted perforated steel cup, such as a phosphorizing cup or an analogous device suitable for this purpose, may be used. Temperatures This invention relates to magnesium-base alloys and 15 of about 1300" to 1400 F. may be used for alloying has for its object the provision of an improved magneoperations. After thorough agitation to insure homosium-base alloy comprising lithium as an essential congeneity, the melt is allowed to settle at temperatures sufi istituent, together with one or more other alloying metals. i nt t maint in it in a hq i State, ft r Which it is More particularly, the invention provides an alloy corndecanted into molds. A suitable casting temperature prising magnesium as the principal constituent, from is, for example, about 1320 F. The alloy may be cast around 1% to 13% of lithium, and one or more othe directly into permanent molds w1thout the necessity of metals, as described hereinafter, which modify and improviding a neutral or reducing atmosphere. prove the physical characteristics of the basic alloy of T0 insur th a s n e f harm l m unts f Sodium magnesium and lithium. or potassium, I prefer to prepare these alloys as described Alloys of the invention are characterized by low spein my copending application, Serial No. 603,749, filed cific gravity, good ductility, high tensile strength and good July 7, 1945, now Patent No. 2,507,713, issued May working properties. A number of these alloys have 16, 1950. In accordance with that application, I may good creep resistance and stability of tensile strength use a flux made up of one part of lithium fluoride to three at room temperature and some are susceptible of heat parts of lithium chloride. Use of such a flux serves to treatment. reduce the sodium and potassium content of the alloy. In accordance with my invention, I provide various I may also treat the alloy by blowing the melt with a alloys of magnesium and lithium together with other gas, such as nitrogen or ammonia, to accomplish a debeneficial metals to form ternary, quaternary and quinary crease in sodium or potassium. alloys having important physical characteristics. As As an illustration of the lightness of these alloys, beneficial metals in the magnesium and lithium basic most of them are lighter than magnesium, having spestructure which I have found and confirmed as useful cific gravities around 1.55. are the following: Aluminum, antimony, barium, beryl- Illustrative examples of alloys of this invention and liurn, bismuth, cadmium, cerium, calcium, chromium, certain of their physical properties are given in the folcopper, indium, lead, manganese, molybdenum, nickel, lowing table:

Per Cent Per Cent Reduc- Yield T all No Percentages ggg tionin Strength str 'iihgt h Area Mg L1 Sn Zn Al 85.20 8.82 3.92 2 28.2 49.2 29,800 35,900

91 Cent N0. Percentages igg ig PIE-155:1); 3 5 2:5 3

Mg Li Sn 84.64 7.36 4 10 4 17.7 23.9 31,600 41,500 26 95.04 3.96 19,0 35.9 15,800 24,900 27 95.04 3.96 19.0 42.0 16,400 26,200 28 93. 12 3. 88 2. 7 13. 5 20. 4 20,300 28, 100 29 M. 89. 74- 8.87 1259 35.7 54.0 18,300 24,200 30 85.26 8.82392 '2 39.5 65.7 1 24,600 31,200 31 s1. 88 10. 12 8 41. 7 44. 1 18, 300 24, 000 32 83. 37. 8. 63 3 35. 7 39. 7 19, 900 27, 300

39 91.0 9.1 1.18 35.7 54.0 18,300 24,200 40 89.7 9.3 i 41.5 62.8 17,500 20,900 41 86.1 8.9 2 1 34.7 62.8 22,600 29,600 42 81.9 Y 10.1 4 4. 28.0 46.8 22,300 29,400 43 81.9 10.1 4 4 10.5 14.8 24,100 31,700 44 84.6 10. 4 if; 36. 5 68. 0 21,200 27, 100 45 87. 4 3. 6 8 1 7. 5 9. 6 31,900 44, 400 46 88.8 I 9.2 1 i 29.7 65.5 23,200 27,400 47 84. 3 8. 7 3 1 7. 7 9. 4 32, 000 39, 500' 48 84. 3 8. 7 1 1 13. 7 14. 3 31, 400 39, 200' 49 84.3 8.7 3 'i 9.7 12.1 31,600 38,800 50 83.4 8.6 3 2 12.0 17.2 31,900 38,300 51---.. 87. 2 10.8 1 1 27. 2 54. 7 26, 500 29, 300 52 84. 5 10. 5 i1: 39. 0 68. 8 18,000 22, 800 53 84. 5 10. 5 1 4 6. 2 10.6 29, 500 33,700 54 90. 2 3.8 2 Ag 16. 0 41. 2 25,000 37, 300 55 9o. 2 3. 8 2 4 16. 5 36. 5 26, 500 39, 800 56 88.3 3. 7 i4} 13. 7 14.6 33,300 47,400 57 87.0 9.0 2 1 1 25.0 56.8 31,200 35,500 58 87. 0 9. 0 2 1 1 27. 0 58. 8 29, 400 33, 700 59 87.0 9. 0 2 1 i 30. 2 60. 4 28, 900 32, 600 60 85. 4 10.6 3 1 1 25. 2 56. 6 28, 900 32, 500 82. 8 10. 2 2 1 4 36. 2 65. 6 20,800 25, 700 82. 8 10.2 2 1 4 5. 2 9. 5 31, 100 35, 100 84.6 6.4 4 i 27.0 38.5 24,100 34,800 84.6- 10.4 i 26.0 56.0 31,800 33,700 84.6 10.4 1% i2 38.7 55.1 19,700 25,000" 31:5 1321 Z i 112:: iii? 5513 31333 353335 84.5 7 10.5 i 4 37.8 61.5 16,000 22,300

I claim: A magnesium-base. alloy consisting 01ab out.2% of zinc, 524,113 about 4% of aluminum, ab011t 2% of tin, about 3.7% 361,086 of lithium, with the balance being magnesium. 509,024

Referencas Cited in the file of this patent FOREIGN PATENTS Great Britain July 30, 1940 Germany Oct. 10, 1922 Germany Oct. 6, 1930 OTHER REFERENCES Serial No. 303,611, Burkhardt (A. P. C.), published Henry et al., Lithium-Magnesium Equilibrium Diagram, Trans. Amer. Inst. Mining and Metallurgical Engrs., 1934, vol. III, pp. 319-332.