Abstract:

The microstructure, texture, residual stress, and tensile properties of Mg-6Zn-2Y-1La-0.5Zr (wt%) magnesium alloy were investigated before and after extrusion process, which performed at 300 °C and 400 °C. The microstructural characterizations indicated that the as-cast alloy was comprised of α-Mg, Mg-Zn, Mg-Zn-La, and Mg-Zn-Y phases. During homogenization at 400 °C for 24 h, most of the secondary phases exhibited partial dissolution. Extrusion process led to a remarkable grain refinement due to dynamic recrystallization (DRX). The degree of DRX and the DRXed grain size increased with increasing extrusion temperature. The homogenized alloy did not show a preferential crystallographic orientation, whereas the extruded alloys showed strong basal texture. The extrusion process led to a significant improvement on the compressive residual stress and mechanical properties. The alloy extruded at 300 °C exhibited the highest basal texture intensity, the compressive residual stress and hardness, and yield and tensile strengths among the studied alloys.

Key words: ZK60, Magnesium alloy, Residual stress, Texture, Mechanical properties Extrusion