Microstructure Formation and Mechanical Properties of a Wire-Arc Additive Manufactured Magnesium Alloy

Abstract

Wire-arc additive manufacturing offers great advantages in terms of design freedom with respect to conventional manufacturing processes. This design freedom translates into additional options for light-weighting, further raised by use of light-weight materials such as magnesium. Here, Cold Metal Transfer is used to manufacture specimens using the magnesium AZ61A alloy. The fabricated deposit has been characterized in-depth in terms of microstructure and mechanical properties. A homogeneous and fine-grained microstructure was observed with no variations in hardness throughout the specimen height. Analyzed second phases are fine due to the high process-intrinsic cooling rates. A weak basal-fiber texture was observed, which is more pronounced in the fusion zone and becomes diffuse in the intralayer region. This texture translates into a weak mechanical anisotropy. The assessment of the mechanical properties suggests values between typical cast and wrought material properties. This study demonstrates the feasibility of processing magnesium alloys by wire-arc additive manufacturing.