HIGH STRENGTH WROUGHT MAGNESIUM ALLOY BY EMPLOYING GRAIN-REFINED POWDER

摘要

Coarse magnesium alloy powder with fine grains less than 5 μm was produced via continuously direct plastic working on coarse raw powder with 0.5～2 mm length, in employing the hot roller compactor system to refine matrix grains and precipitate some intermetallic compounds. In particular, dynamic recrystallization of the matrix grains during the warm plastic working causes the refinement of grains and the drastic hardening. When optimizing the process parameters of the plastic working such as the roll surface temperature, number of cycles in working and clearance between twin rollers, AM60 wrought magnesium alloy after hot extrusion shows UTS of 380 MPa and 6 % elongation at room temperature. It reveals uniformly refined microstructure, in particular the mean grain size of 1.4 μm.