Establishing Molten Pool Thermal History Based Process Map for Ultrasonic Vibration Assisted Ex‐Situ and In‐Situ Laser Cladding of TiN/Inconel 625 Metal Matrix Composite

This study develops process map based on melt‐pool thermal history to predict microstructure and phases for ex‐situ and in‐situ laser cladding of TiN/Inconel 625 metal matrix composites under the implementation of ultrasonic vibration, reducing the need for extensive post‐deposition phase analysis. The ex‐situ cladding uses TiN and Inconel powder, whereas in‐situ route uses nitrogen in gaseous form. Retention or decomposition of reinforcement and formation of different phases depend on process parameters and deposition routes. This study addresses the effect of external agitation, along with process parameters, like line energy and N 2 gas pressure, on microstructural changes and phase formation, as well as develops correlation map for identifying the phase change through specific signatures of thermal history graphs. In ex‐situ deposition, line energy influenced the TiN decomposition and consequent formation of Ti‐Ni intermetallic and TiN. Conversely, for in‐situ process, nitrogen flow rate controlled the formation of TiN. Furthermore, ultrasonic vibration led to the formation of Fe‐Ni phase due to stronger melt‐pool convection. Accordingly, thermal history graphs showed solidification shelves at 1670–1800 °C and 950–1100 °C, corresponding to TiN and Ti‐Ni compounds, while solidification shelves at 1420–1500 °C indicated Fe‐Ni phase formation. These signatures provide relevant information on phase formation under distinct processing conditions.