Friction welding of Al-12Si parts produced by selective laser melting

Al-12Si samples produced by selective laser melting (SLM) are welded using solid-state friction welding. The weld metal shows the presence of texture with excess Si diffusing out from the Al matrix. Microstructural investigations reveal a pronounced change in the shape and size of the Si phase in the weld metal compared to the base material, with the formation of extremely fine particles uniformly distributed in the Al matrix. This variation in the microstructure is expected to have significant changes in the mechanical properties of the welded material. The hardness measurements reveal a drop of hardness in the weld zone with respect to the base metal. Similarly, the room temperature tensile tests show a significant improvement of ductility in the welded SLM samples. However, the yield and the ultimate strength show only a marginal drop in the welded samples compared to the as-prepared SLM specimens. The present work demonstrates that solid-state friction welding not only permits to successfully join materials produced by SLM, but also helps to significantly improve their ductility. (C) 2014 Elsevier Ltd. All rights reserved.