THE EFFECT OF SMALL ADDITIONS OF SILVER ON THE MECHANICAL PROPERTIES OF ALUMINUM CASTING ALLOYS.
ARMY WEAPONS COMMAND ROCK ISLAND ILL RESEARCH AND ENGINEERING DIV
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The report presents significant test results showing that 0.3 silver additions to melts of certain aluminum casting alloys, 40E and Precedent 71A, increase the yield and tensile strengths without large loss of ductility. Yield strength improves 80 and tensile strength 45 in test-size castings of silver treated 40E alloy, after solution-precipitation treatment yield and tensile strengths increase more than 13 each, in machined specimens from end-chilled plates. A one week delay between solution treatment and artificial aging of the standard 40E alloy improves the yield and tensile strengths more than 30 each, but no additional improvement occurs in the silver-treated alloy. After artificial aging only, test-size castings from the silver treated alloy increase more than 25 in yield and 10 in tensile strength machined specimens from plates improve more than 15 in yield and 5 in tensile strength. Only marginal gain in yield strength occurs after natural aging for 40 days. Remelting of the alloy does not destroy the beneficial effects of silver additions. Silver improves the yield strength 5 to 10 in Precedent 71A alloy after solution-precipitation treatment. Author
- Properties of Metals and Alloys
- Fabrication Metallurgy