Effect of sintering temperature on microstructure, grain boundary characterization and mechanical behaviour of hot-press sintered Ti-6Al-4V alloy

This study investigates the influence of sintering temperature during hot pressing on the microstructural evolution, mechanical behaviour, and grain boundary characteristics of the Ti-6Al-4V alloy. The pre-alloyed Ti-6Al-4V powder was subjected to hot pressing at sintering temperatures of 800 °C, 900 °C, 1000 °C, and 1100 °C under vacuum at a uniaxial pressure of 45 MPa. Microstructural analysis using optical microscopy, field-emission scanning electron microscopy (FESEM), and electron backscatter diffraction (EBSD) revealed significant changes in grain morphology and microstructural evolution with increasing sintering temperature. Mechanical properties were evaluated by conducting tensile tests on sintered compacts. A tensile strength of 944 MPa and better ductility were observed in Ti-6Al-4V sintered at 900 °C. The sample's microstructure exhibited equiaxed and lamellar structures and a fine particle size. At higher temperatures, while densification improved, excessive grain coarsening led to a decline in mechanical performance. These findings highlight the importance of sintering temperature in enhancing the performance of Ti-6Al-4V alloys processed via hot pressing, with 900°C as the optimal condition for achieving improved mechanical properties. • Hot Press Sintering process of pre-alloyed Ti6Al4V was performed at 800–1100 °C for 30 min under 45 MPa in vacuum atmosphere. • Microstructure, grain boundary characteristics and mechanical properties of hot press sintered pre alloyed Ti6Al4V were studied. • Fine grain size with denser microstructure and better mechanical performance was obtained at 900 °C. • Maximum density and hardness were obtained at 1100 °C.