HEAT TREATMENT FOR MICROSTRUCTURE STABILIZING OF BIOMEDICAL TI-6AL-4V ALLOY FABRICATED BY SELECTIVE LASER MELTING

In this study, the microstructural evolution of the microstructure and phase transformation of the biomedical Ti-6Al-4V alloys fabricated by Selective Laser Melting (SLM) at various solution treatment temperatures was investigated in order to achieve the formation and stabilization of (α + β) lamella structure for the final products. Solution heat treatments were conducted at 850℃ for 2.5 hours; at 950℃ or 1020℃ for 1 h and followed by cooling naturally in the oven. The α' martensite in the SLMed samples was transformed from the β phase after heat treatment and finally achieved the uniform (α + β) lamella structure in heat treated samples of Ti-6Al-4V alloys. The dependence of the transformation behavior of the β phase during the solution treatment was determined by the partitioning of α and β stabilizing elements.