PBF-LB/M of Ti-6Al-4V: High-Pressure Solution Treatment and Aging for Applications in a Sustainable Aerospace

Abstract

Additive manufacturing allows great geometric freedom for lightweight components. As parts are progressively optimized in terms of topology and weight reduction in order to exploit potentials in additive manufacturing leading to smaller material cross sections, high-pressure solution treatment and aging heat treatments show an enormous potential for a more sustainable aviation by strongly improving material properties. In this work, the previous aerospace standard for Ti-6Al-4V (STD) at 920°C and 105 MPa of pressure is compared with the new low temperature and high-pressure standard (LTHP) at 815°C and 190 MPa and two high-pressure solution treatments and aging in α+β phase field at 930°C (ST_α+β) and super-T _β at 1050°C (ST_β), both at 105 MPa of pressure. As for LTHP the tensile strength can be increased by up to 8% compared to STD, the Charpy impact toughness decreases strongly by –19%. By ST_α+β the strength can be further increased by up to 14% compared with STD, while the Charpy impact toughness being –9% of STD is considerably higher compared to LTHP. Our study shows great potential for high-pressure solution treatment and aging of Ti-6Al-4V exploiting the potential of the initially super fine microstructure in terms of pore closing, high strength, ductility, and toughness.