1992 Volume 42 Issue 6 Pages 345-351
Rapidly solidified flakes of AZ91 magnesium based alloys with or without addition of Si, Ni, Ce were produced by atomizing the alloy melt and subsequent splat quenching onto a water-cooled copper roll. Consolidation of the flakes was carried out by cold pressing and hot extrusion at a reduction ratio of 25:1. Higher tensile strength at room temperature was obtained for as-extruded materials than for T6-treated ones due to softening observed during solutionizing heat treatment. The as-extruded material of Si-bearing alloy showed the highest tensile strength of 371MPa. However, as-extruded materials showed lower strength and higher elongation at higher testing temperatures because of their fine grained structures. At 573K, superplastic elongation as high as 415% was observed. It is postulated that the P/M materials with high specific strength at room temperature combined with very high ductility at elevated temperatures can be obtained by applying rapid solidification to magnesium based alloys.
