2017 Volume 58 Issue 7 Pages 1089-1092
The possibility for reduction in tension-compression asymmetric behavior and the effect of alloying elements on room temperature compressive behavior were investigated using extruded pure magnesium, several Mg-0.3 at.%X (X = Al, Li, Mn, Y and Zn) binary alloys and the commercially AZ31 alloy. They had fine-grained structures of an average grain size of 3–5 μm, except for the AZ31 alloy. The compressive deformation behavior was influenced by the alloying elements. The Mg-Al, Mg-Zn and Mg-Y alloys showed sigmoidal shaped stress vs. strain curves, irrespective of the strain rates, due to the contribution of deformation twinning. On the other hand, pure magnesium and those alloys added with manganese or lithium as alloying elements did not exhibit such stress vs. strain behavior. Instead of deformation twinning, they had high strain rate dependence, i.e., the m-value of more than 0.1, which indicated that grain boundary sliding played an important role in deformation during compression testing. Under such a condition, in particular for the strain rates of 10−4–10−5 s−1, it is interestingly noted that these specific materials showed isotropic tension-compression behavior. They also displayed good room temperature deformability, such as accordion-like deformation, which has never been observed in magnesium alloys.
