Optimizing the local microstructure and mechanical properties of variable section particulate reinforced titanium matrix composites component based on numerical simulation and isothermal forming

To solve the precision forming problem of titanium matrix composites (TMCs) precision components with variable cross-sections, isothermal compression model of (TiB + La2O3)/IMI834 composite was established to investigate the deformation behaviors, determine forming strategy, predict and optimize the local microstructure. The subsequent isothermal precision forming experiment proved the precision forgings can be successfully fulfilled with good surface quality in one step using a cylindrical billet following the simulation strategy. Referring to simulation results, the local microstructure and performance were successfully optimized by controlling the deformation degree in different section regions to meet the service requirements. Fine-grained regions and reinforcement-rich regions were formed in the small cross-section (large deformation) regions due to the rotation and directional arrangement of the reinforcements and the dynamic recrystallization stimulated by the reinforcements, where the engineering strength and elongation were both improved from 1137 MPa and 2.55% to 1176.5 MPa and 4.0%, respectively, compared with the large cross-section (small deformation) regions. This research provided an important guidance for improving the fabrication efficiency and optimizing the local microstructure and performance of TMCs precision components by isothermal forming.