Exploration on mechanical response mechanism of laser melting deposited TiB <sub>W</sub> /Ti–6Al–4V via <i>in situ</i> characterisation technology
Yaya Wu, Anan Guo, Jianqiang Yuan, Lin Zhang, Yan Wen, Lin Hua, Lai‐Chang Zhang, Lechun Xie
Abstract
The processing parameters of laser melting deposition (LMD) can significantly influence the microstructure and properties of LMD components. Herein, we manufactured TiBw/Ti–6Al–4V titanium matrix composite (TMC) using LMD, aiming to obtain the optimal preparation parameters. The electrical resistivity of the TMC first decreased and then increased, which was related to the microstructural evolution. TiBw network was formed in the matrix during LMD, indicating the in situ reaction of TiB2 during LMD. The reinforcement TiBw was tended to precipitate preferentially during solidification. In situ tensile experiments indicated that LMD TiBw/Ti–6Al–4V exhibited an ultimate strength of 1314 MPa and a plastic strain of 1.0% at room temperature, while the ultimate strength of 784 MPa and the plastic strain of 1.4% at 600℃. This is attributed to the different underlying deformation mechanisms at room temperature and high temperature. At room temperature, TiBw was first fractured brittlely under deformation, and the cracks propagated to the matrix. By contrast, the high temperature tension caused TiBw failure due to the interfacial stress concentration. Our findings provided valuable insights into adopting appropriate parameters for LMD high-performance TMCs.