Microstructure and mechanical properties of Mg-2Sn-1.95Ca-0.5Ce alloy with different extrusion speeds

Abstract

Effects of extrusion speeds (0.3, 1.2, 1.8 and 3.5 mm s ^−1 ) on the microstructure and mechanical properties of the Mg–2Sn–1.95Ca–0.5Ce (TXCe220) alloy were analyzed by various detection methods in this article. The results have revealed that extrusion speed exerts a prominent influence towards grain size, recrystallization fraction and texture. As the extrusion speed increases, the microstructure characteristics transform from bimodal grain morphology to the near complete dynamical recrystallization (DRX). The tensile yield strength of TXCe220 decreased from 365 MPa to 180 MPa accompanied by the elongation increasing from 4.0 % to 19.4 % when the ram speed rises from 0.3 mm s ^−1 to 3.5 mm/s. The high yield strength of low-speed extruded alloys should be mainly ascribed to the nano-scale Mg _2 Ca with diameter of 30–80 nm precipitates, fine DRX grains and strong texture.

Keywords

• magnesium alloy
• extrusion speed
• dynamic recrystallization
• mechanical properties