Numerical Simulation, Microstructure, and Properties of TC4 Plasma Arc Additive Manufactured Thin Wall

Titanium alloys are widely used in aerospace and other fields due to their high strength, excellent wear resistance, corrosion resistance, biocompatibility and non-magnetic properties. This study validates the temperature evolution of 6-layer TC4 thin-walled parts through simulations and experiments. The simulations were reliable and accurate. The build process was performed by plasma arc additive manufacturing (PAAM) process. Further, the thermal elastic–plastic model and thermal stress field simulation of PAAM performed in reciprocating scanning sequence and unidirectional scanning sequence was carried out. Results showed alternating temperature gradients and uniform residual stress distribution in the reciprocating sequence. PAAM of TC4 thin walls in reciprocating scanning achieved excellent finish, accuracy, and no visible defects. The strength of the wall met ASTM forging standards. Microstructural analysis revealed reduced β phase and improved α phase through PAAM deposition. The lower region had Widmanstätten structure and basket-weave morphology, while the middle portion had relatively coarse basket-weave structure. The top region exhibited martensite structure and basket-weave structure. Tensile tests showed different strengths in scanning and build directions. Ultimate tensile strengths were 1013.7 and 965.1 MPa, with elongations of 6 and 7.9