Study on selective laser melting and heat treatment of Ti-6Al-4V alloy

The effects of process parameters of laser additive manufacturing (laser power, scanning speed, scanning direction) and heat treatment on the microstructure and properties of Ti-6Al-4V titanium alloy forming parts were studied under coaxial powder feeding. The results show that the columnar crystals of the Ti-6Al-4V forming parts made by laser material are all wechsler structure, and there are obvious layers in the layer; the strength of laser reinforced Ti-6Al-4V titanium alloy parts exceeds the requirements of national standard for as cast and forged Ti-6Al-4V titanium alloy; With the increase of laser power, the tensile strength and yield strength of Ti-6Al-4 V titanium alloys tend to increase first and then decrease, and the maximum value is obtained when the laser power is 500 W; when the scanning speed increased from 0.12 m/min to 0.60 m/min, the tensile strength and yield strength of the Ti-6Al-4V titanium alloy showed a gradual decrease, but the elongation gradually increased; when the laser scanning mode is changed from single sweep to round-trip scanning, the tensile strength and yield strength of Ti-6Al-4V titanium alloy have been improved, but the elongation has decreased significantly. Through the solution and aging heat treatment at 950 °C/AC/1 h + 540 °C/AC/4 h, the original wechsler structure can be improved and the high performance net basket organization can be obtained, this is the fundamental reason for improving the comprehensive performance of the forming parts.