STRUCTURE AND PROPERTIES OF A RAPIDLY QUENCHED COMMERCIAL Al-Mn ALLOY.

Microstructure and mechanical properties of a melt-quenched commercial Al-Mn alloy have been investigated. The foils obtained by the combined 'gun' and 'piston-and-anvil' method are about 100 mu m thick in the center and had a microhardness value of about 480 MPa. They have been annealed at different temperatures and the hardness measured as a function of time. The aging curves showed a peak value suggesting the tendency for precipitation hardening. Annealing at 573 K for 10 h resulted in a maximum hardness of 620 MPa, tensile strength of 205 MPa, and 0. 1% proof stress of 162 MPa for this alloy. The as-quenched foils contained only a supersaturated solid solution, which was quite stable up to about 523 K. Decomposition of the supersaturated solid solution at higher temperatures led to the precipitation of intermediate phases.