한국주조공학회

In this study, the powders of Mg-3wt%Al-lwt%Zn-1wt%MM alloy were produced under vacuum condition by the inert gas atomization and the rapidly solidified powders were consolidated by the vacuum hot extrusion. Then the structural change of powders during exmsion was investigated. The effects of misch metal addition to AZ31 on mechanical properties of extruded bars were also examined. During extrusion of the rapidly solidified powders, their dendrite structure was broken into frag- ments and remained as grains of 2 um size in extruded bar. The Mg-Al-Ce intermetallic compounds formed in the interden- dritic regions of powders were broken finely, too. The yield stress, tensile strengh and ductility obtained in as~extruded Mg- 3wt%A1-lwt%Zn-lwt%MM alloy were 0'0'2=325 MPa, GT_S_=4l7 MPa and €=l6.8%. All of these improvements on mechan- ical properties result from the refined micostructure and second-phase dispersions.