Tension–Compression Asymmetry Improved by Cold Extrusion in Pure Magnesium

Abstract

In this paper, cold extrusion was successfully used to fabricate the fine-grained pure Mg bar with average grain size of 2.5 μm. The microstructure, texture and mechanical properties were evaluated by electron backscattering diffraction and mechanical test. The results showed that the corresponding yield strengths for as-extruded fine-grained pure Mg were 130.8 MPa in tension and 125.6 MPa in compression, leading to a greatly improved yield asymmetry ratio. The improvement in tension–compression asymmetry is mainly due to grain refinement which favors the suppression of deformation twinning in compression and promotion of multi-deformation modes both in tension and compression at small strains.