Evaluation of heat treatment parameters on microstructure and hardness properties of high-speed selective laser melted Ti6Al4V

Abstract

This study presents the investigation on how heat treatment parameters, which are temperature, cooling method, and residence time, influence the microstructural and hardness properties of Ti6Al4V components produced on Ti6Al4V substrate using high speed selective laser melting technique. Heat treatment was performed on the produced samples before they were characterized for microstructure and hardness. The microstructure of the as-built sample contained large columnar ß-grains that were filled with martensite a’ phase and had a high hardness of 383 ± 13 HV. At 1000 C and residence time of maximum 4 h, better heat treatment parameters were seen for the selective laser melting (SLM) produced Ti6Al4V sample since an improved lamellar a + ß microstructure was obtained at this condition. This microstructure is known to have improved tensile properties.