A comparative study of hot deformation behavior between powder sintering and forged ingot TA15 alloys

This work examined the hot deformation characteristic and microstructure of powder metallurgy and forged ingot TA15 alloy using isothermal compression testing. During deformation, the temperature, peak stress and strain rate adhere to the Arrhenius hyperbolic sine function relationship. Within the temperature range of 900–1200 °C and a strain rate of 0.01–10 s⁻¹, the stress factor (α) for powder-sintered and forged TA15 billets is 0.018 and 0.020, respectively, while the strain rate sensitivity index n is 3.735 and 3.333, respectively. The thermal deformation activation energies are 172.616 and 159.914 kJ/mol, respectively. The results show that the optimal hot working window of TA15 powder sintered billet is 900–1200 °C/0.01–10 s⁻¹, and the temperature is increased by 164 °C and the strain rate range is higher than that of TA15 forging billet. Following hot deformation at 1100 °C, the powder sintered billet exhibits a fine basket-weave microstructure. While, the forged billet has a coarse equiaxed microstructure with a grain size reaching the millimeter scale.