Effect of Heat Treatment on Mechanical Properties of Porous Ti55531 Alloy Prepared by Selective Laser Melting

Lightweight metallic cellular components with high strength have received extensive interest because they are desirable for structural components. Previously, titanium alloy cellular structures were formed using additive manufacturing with the selective laser melting or electron beam melting technique. Numerous techniques have been developed to improve their strength. Most of these studies have focused on structure topology design. The relationship between the strength and mechanical properties of their strut parent materials has gained considerable attention. XRD, OM, SEM, and compression tests were used to investigate the effects of heat treatment on the microstructure and mechanical properties of Ti-5Al-5Mo-5V-3Cr-1Zr (Ti55531) alloy porous materials prepared through selective laser melting. The results show that the microstructure in struts consist of alpha and beta phases after solution treatment at a temperature between 750 degrees C and 900 degrees C followed by an aging treatment at a temperature between 500 degrees C and 600 degrees C. The volume fraction of the primary alpha phase in the struts decreases as the solution temperature rises, whereas the volume fraction of the secondary alpha phase increases. The strut parent material's compressive strength increases but its elongation decreases, resulting in a decrease in toughness. With the increase of aging temperature, the shape, size, and volume fraction of the primary alpha phase in the strut do not change considerably, whereas the volume fraction of the secondary alpha phase decreases and the size increases. The strut parent material's compressive strength decreases while elongation increases, increasing toughness. The compressive strength of the examined porous alloy is strongly connected to the toughness of the parent material of the struts, which can be effectively improved by adjusting the strength and plasticity of the struts through heat treatment. The above results will guide the design of lightweight metallic cellular components with high strength.