Improvement of mechanical properties and microstructural refining of cast titanium alloys by coupling of electropulsing and temporary alloying element hydrogen

The electric pulse treatment and hydrogen as temporary alloying element have been widely used to improve the microstructure and mechanical properties of titanium alloys, respectively. In this study, the microstructure and mechanical properties of as-cast Ti-6Al-4V alloy are improved by electric pulse treatment combined with temporary alloying element hydrogen instead of traditional thermo-mechanical treatment and heat treatment. In comparison to the traditional thermo-mechanical treatment, the microstructure of the as-cast Ti-6Al-4V alloy after solution-aging treatment in pulsed thermal hydrogen treatment is homogeneous and finer, which is due to the lamellar 8 phase decomposition after thermal hydrogen treatment, accordingly, the ultimate tensile strength and total elongation of the alloy are effectively improved after pulsed thermal hydrogen treatment. It's the acceleration of atomic diffusion and phase transformation in titanium alloys by hydrogen as temporary alloying element and electric pulse treatment that leads to the decomposition of the lamellar 8 phase, thereby refining the microstructure and enhancing mechanical properties. Finally, a novel method for improving the microstructure and mechanical properties of titanium alloys using hydrogen as temporary alloying element and electric pulse treatment is presented.