AGE-HARDENING IN BERYLLIUM-ALUMINUM-SILVER ALLOYS

Three different alloys of beryllium-aluminum-silver were processed to powder by centrifugal atomization in a helium atmosphere. Alloy compos itions were, by weight percent, Be-47.5Al-2.5Ag, Be-47Al-3Ag, and Be46 Al-4Ag. Due to the low solubility of both aluminum and silver in beryl lium, the silver was concentrated in the aluminum phase, which separat es from the beryllium in the liquid phase. A fine, continuous composit e beryllium-aluminum microstructure was formed, which did not signific antly change after hot isostatic pressing. Samples of hot isostaticall y pressed material were solution treated at 550 degrees C for 1 h, fol lowed by a water quench. Aging temperatures were 150, 175, 200, and 22 5 degrees C for times ranging from half an hour to 65 h. Results indic ate that peak hardness was reached in 36-40 h at 175 degrees C and 12- 16 h at 200 degrees C aging temperature. relatively independent of all oy composition. Copyright (C) 1996 Acta Metallurgica Inc.