Effect of mechanical alloying on the properties of rapidly solidified Al-Mn base alloys

Rapidly solidified flakes of Al-8%Mn alloys containing Fe, Cr, Co, Ce, Fe+Ni were produced by using an apparatus combining atomization and water-cooled single copper roll. The flakes were MA processed for 30 h by a high energy ball mill. Consolidation of the flakes and MA powder was done by cold pressing, degassing and hot extrusion. The effect of MA processing on the properties of rapidly solidified Al-Mn base alloys was studied. Hardness, strength and thermal stability of rapidly solidified Al-8%Mn alloy were improved by addition of the third elements, and P/M materials with 4%Co addition showed the highest improvement. The properties were further improved by applying MA, due to fine and uniform dispersion of aluminides, oxide and carbide. MA-P/M materials with 2%Ni+2%Fe addition showed tensile strengh as high as 700MPa at room temperature, and those with 4%Co addition showed the highest tensile strength of about 230MPa at 573K. However, ductility was decreased by MA treatment.