Solidification texture dependence of the anisotropy of mechanical properties and damping capacities of an AZ31 Mg-based alloy fabricated via wire-arc additive manufacturing

Abstract

Wire-arc additive manufacturing (WAAM) offers a brand-new method for short process and rapid manufacturing of large magnesium alloy components, which can avoid the formability dilemma faced by Mg alloys due to their poor plasticity. In this study, the relationships between the solidification texture and the anisotropy of mechanical properties/damping capacities of an AZ31 Mg-based alloy fabricated by the WAAM process were studied. The results revealed that the crystallographic texture with the (0001) basal plane along the building direction was promoted by the preferential growth of dendrite arms along the <11–20> direction of the HCP crystal structure. The (0001) basal texture had a strong influence on the anisotropy of mechanical properties and damping capacities. Compared to the sample with a tensile axis perpendicular to the building direction, the sample with a tensile axis along the building direction displays a simultaneous increase in tensile strength and ductility, which is related to the smaller Schmid factor (SF) for basal <a> slip and better plasticity deformation via non-basal slip and twinning. However, the smaller SF for basal <a> slip also results in a smaller resolved shear stress factor for the breakaway stress during the damping response testing, resulting in lower damping capacities. This work is helpful for further optimizing the mechanical properties and damping capacities of WAAM-processed Mg-based alloys.