Effect of Heat Treatment Temperature on Microstructure and Mechanical and Tribological Properties of Cold Sprayed Ti-6Al-4V Coatings

Abstract

ABSTRACTIn this study, Ti-6Al-4V (Ti-64) coatings were prepared on commercial Ti-64 substrates via a high-pressure cold spray process. The coatings were heat treated at different temperatures of 400–1000°C to investigate the effect of heat treatment temperature on their microstructure and mechanical and tribological properties. The increased heat treatment temperature from 400 to 600°C promoted diffusion between sprayed Ti-64 particles. Recrystallization of the sprayed particles was found at the heat treatment temperature of 800°C and grain growth was found in the microstructure of the coating heat treated at 1000°C. The highest and lowest hardnesses of the heat-treated coatings were found at heat treatment temperatures of 400 and 800°C, respectively. Therefore, the lowest and highest specific wear rates of the coatings were consistently found at 400 and 800°C due to their highest and lowest abrasive wear resistances associated with their highest and lowest surface hardnesses, respectively. The coating heat treated at 400°C showed the highest surface hardness of 470.1 Hv and lowest specific wear rate of 69.6 × 10−14 m3/Nm. It could be concluded that the microstructure and mechanical and tribological properties of the Ti-64 coatings were significantly influenced by heat treatment temperature.