HIGH-STRENGTHENED MAGNESIUM ALLOY WITH ULTRA-FINE MICROSTRUCTURES USING RAPID SOLIDIFICATION PROCESS AND ITS APPLICATIONS

摘要

Modified water-atomization process was employed to prepare rapidly solidified non-combustive magnesium alloy powders containing calcium (Ca) elements. They were pressed by warm compaction, and subsequently applied to hot extrusion. Wrought P/M Mg-Al-Ca-La alloys consisted of fine and uniform grained with less than 1 um in diameter via dynamic recrystallization behavior. Intermetallic compounds such as Al_2Ca and AlllLa with 300-500 nm were dispersed in the matrix. This material showed a good balance between tensile strength and ductility such as TS of 400-420 MPa and 15-20% elongation at room temperature. It also revealed high dynamic strength of fatigue property and impact energy absorption performance. The main strengthening mechanism of this alloy was grain refinement, and it means that thermal control in powder consolidation strongly dominates the microstructural and mechanical properties of the alloys.