Effect of initial texture on fatigue properties of extruded ZK60 magnesium alloy

Abstract

AbstractThe effect of initial texture on cyclic deformation behavior of extruded ZK60 magnesium (Mg) alloy was experimentally investigated under strain‐controlled loading with the strain amplitudes at 4%, 1%, and 0.35%. The testing specimens were taken from extrusion direction (ED), transverse direction (TD), and a material precompressed to 9.4% along the ED (ED−9.4%). At a high strain amplitude of 4%, the cyclic deformation modes of ED and ED−9.4% specimens are similar, and they experience twinning exhaustion → <c + a> slip and detwinning exhaustion → <c + a> slip during each loading cycle. At a medium strain amplitude of 1%, twinning‐detwinning is involved in the cyclic deformation, but different deformation mechanisms were observed in the 3 different specimens. Partial twinning‐complete detwinning mode dominates the cyclic deformation in the ED specimen, while partial detwinning‐retwinning mode occurs in the ED−9.4% specimen. For the TD specimen, both <a> basal slip and tension twinning occur during cyclic deformation. At a low strain amplitude of 0.35%, dislocation slips dominate the deformation for the ED specimen with a few observable tension twins. For the ED−9.4% specimen, initially twined texture increases the ductility of the material and enhances fatigue life as compared with the other 2 specimens.