Mechanical and thermal stability of powder metallurgy aluminum-titanium alloys

Al--4Ti and Al--6Ti powders were prepared using helium gas atomization, mechanical alloying of Al powders and Al3Ti intermetallics, and mechanical alloying of the prealloyed Al--Ti atomized powders. The powders were vacuum hot pressed and extruded into rods and the microstructural and mechanical stability on annealing were assessed using microhardness and notched-tensile tests. Both alloys exhibited excellent thermal stability even after 100 h exposure at 500 deg C. Mechanical alloying, in contrast to inert gas atomization, introduces carbides and oxides to the system, causing increased strength, higher hardness and reduced ductility. 14 ref.--D.O.N.(UK/US).