Abstract
P/M Al-Li alloys containing a large amount of Mn were made by using a rapid solidification technique to prevent the formation of coarsened Al6Mn phase. The changes in mechanical properties and microstructures of these alloys with aging time were examined. The solute Mn does not depress the precipitation hardening ability of Li, but increases linearly the hardness and tensile strength, especially Young's modulus, of the as-extruded or as-quenched alloys with its amount. Most of the solute Mn is dispersed in the matrix as the Al6Mn particles the size of which is in an order of submicron. Heat treatment usually employed for the Al-Li alloy adds the precipitation hardening by Li to the hardening (dispersion type) by Mn mentioned above. Increases in the density of the Al-Li-Mn alloys with increase in Mn content can be compensated for by Li.
