Microstructure and Micro-texture Development of Variable Frictional Heat Input Friction Stir Welded Joints of Laser Powder Bed Fusion-Made AlSi10Mg Plates

In this study, friction stir welding (FSW) joints of additively manufactured (AM) AlSi10Mg alloy, that is, medium heat input (joint 01), high heat input (joint 02), and low heat input (joint 03), were investigated to study the effect of frictional heat input on micro-texture evolution. A preliminary optical and SEM–EDS investigation revealed a homogeneous distribution of Al-Si particles in the high- and low-heat-input welded joints with an average particle size of 1.4 and 2.4 µm, respectively. In contrast, onion rings were only formed when the material flow was just right at a medium heat input, resulting in the highest ultimate tensile strength of 237 MPa among the three joints. Furthermore, the micro-texture analysis revealed that A/Ā ({1 \(\overline{1 }\) $\overline{1}$ 1}<110>/{1 \(\overline{1 }\) $\overline{1}$ 1}< \(\overline{1 }\overline{1 }\) $\overline{1}\overline{1}$ 0>) simple shear micro-textures with a slight C {001} <1 \(\overline{1 }\) $\overline{1}$ 0>  were dominant in welds with superior mechanical strength, that is, medium-heat-input weldments. In contrast, the A^*₁/A^*₂ ({11 \(\overline{1 }\) $\overline{1}$ } <2 \(\overline{1 }\) $\overline{1}$ 1>/{11 \(\overline{1 }\) $\overline{1}$ } <112>) shear components are more prominent in low- and high-heat-input weldments.