Microstructure and mechanical properties of in-situ formation TiB2 reinforced TC4 joint prepared via corona model laser welding

Titanium matrix composites have excellent specific strength, specific stiffness and wear resistance. In this work, (TiB + TiC) multiphase ceramic reinforced Ti6Al4V joints were successfully prepared using corona model laser welding coupled with powder feeding fusion injection technique. SEM, EBSD techniques were used to evaluate the joint formation, the microstructure evolution was characterized and discussed in depth, and the tensile properties were evaluated. The results shown that excellent formed Y-shape joints are obtained with increasing powder melt injection rate at the same linear energy. In-situ (TiB + TiC) multiphase ceramic particles were generated in the welded joints, and the particles exhibited characteristic of distribution along the grain boundaries. The in-situ generation of (TiB + TiC) composite ceramic particles significantly increased the microhardness of the weld area, and the tensile strength of the weld area could reach 1368 MPa. There is no doubt that this work has successfully combined the melt injection technique with corona model laser welding technique to produce well-formed and high performance titanium matrix composite joints.