Microstructure and mechanical properties of Mg-2Zn-0.3Ca-0.5La magnesium alloy extruded with different temperatures

Abstract

The extrusion tests of the Mg-2Zn-0.3Ca-0.5La (ZXLa200) alloy were carried out at different extrusion temperatures (260 °C–320 °C), and the mechanical properties and microstructure were studied and analyzed by means of optical microscope, scanning electron microscope, x-ray diffraction, transmission electron microscope, and tensile testing. The research have demonstrated significant influence of Extrusion temperature towards grain size, recrystallization grains and texture. With the extrusion temperature increases, the recrystallization grain of the extruded ZXLa200 alloy increases, but the texture intensity decreases. During the extrusion process, a large amount of Ca2Mg6Zn3 (50–200 nm) precipitates are precipitated, which inhibited the growth of dynamic recrystallization grains and improved the yield strength of the alloys. The tensile yield strength and elongation of extruded ZXLa200 alloy were acquired to be 375 MPa, 5.9% at 260 °C and 310 MPa, 19.2% at 320 °C.