Evolution of Microstructure and mechanical properties of selective laser melted Ti-5Al-5V-5Mo-3Cr after heat treatments

摘要

Titanium alloy Ti5553 (Ti-5Al-5Mo-5V-3Cr) is an excellent candidate for structural applications and additive manufacturing processes, since, unlike Ti6Al4 V, when built via selective laser melting and/or post additive manufactured welding, it maintains a near-beta microstructure that is both ductile and high strength. Another feature is that Ti5553 properties are adaptable through post build heat treatment. This study explores the heat treatability of selective laser melted Ti5553 up to temperatures approaching the beta-transus. Results show strength increases while maintaining ductility at high temperatures (700-800 degrees C), but embrittlement occurs at intermediate temperatures (400-600 degrees C) likely due to changes in volume fraction and morphology of the alpha-phase and/or the presence of the omega-phase. Microstructure and X-ray diffraction are reported after heat-treating to better understand this mechanical response.