Texture and its effect on mechanical properties in fiber laser weld of a fine-grained Mg alloy

A fine-grained Mg alloy was fiber-laser welded, and microstructures and texture in the welds were extensively examined, together with the effect on mechanical properties. Fusion zone, which has lower hardness than BM and HAZ, consists of columnar grain zone and equiaxed grain zone with coarser grains. Strong texture with the same orientation as base metal forms at columnar grain zone. With decreasing welding heat input, yield strength of the welded joint increases due to the finer microstructures; however, ultimate tensile strength as well as elongation decreases because of the deterioration in deformation capacity induced by the diminishment of the width of equiaxed grain zone.