The recrystallization temperature and extruded structure of Al-4% Mn alloys

Abstract

Some properties such as recrystallization temperature, hardness, structure, etc. of cold rolled and hot extruded Al-4% Mn alloys were studied.Results obtained were as follows:(1) The recrystallization phenomena after cold rolling of Al-1-4% Mn alloys prepared by sand mold casting depended upon pre-treatments before the rolling. It was found that the recrystallization temperature of these alloys after heat treatment at 630°C was higher in the case of water quenching than that of slow cooling.(2) The recrystallization temperature of rolled Al-4% Mn prepared by metallic mold casting was found to be about 425-450°C, being higher than that of the said alloys prepared by sand mold casting.(3) The microstructure of extruded binary Al-4% Mn alloys and most of the said alloys containing 0.5-1.0% of each one of additional elements (such as Ca, Cr, Fe, Mg, Nb, Si, Ti, V, and Zn) was found to be very fine. Especially, in metallic mold casting, the formation of these fine structures was caused by containing fine compounds, which had been precipitated from α solid solution during the extrusion at 550-580°C.