Additive friction stir deposition of AZ31B magnesium alloy

The current work explored additive friction stir deposition of AZ31B magnesium alloy with the aid of MELD® technology. AZ31B magnesium bar stock was fed through a hollow friction stir tool rotating at constant velocity of 400 rpm and translating at linear velocity varied from 4.2 to 6.3 mm/s. A single wall consisting of five layers with each layer of 140×40×1 mm3 dimensions was deposited under each processing condition. Microstructure, phase, and crystallographic texture evolutions as a function of additive friction stir deposition parameters were studied with the aid of scanning electron microscopy including electron back scatter diffraction and X-ray diffraction. Both feed material and additively produced samples consisted of the α-Mg phase. The additively produced samples exhibited a refined grain structure compared to the feed material. The feed material appeared to have a weak basal texture, while the additively produced samples experienced a strengthening of this basal texture. The additively produced samples showed a marginally higher hardness compared to the feed material. The current work provided a pathway for solid state additive manufacturing of Mg suitable for structural applications such as automotive components and consumable biomedical implants.