Deep Cryogenic and Thermal Aging Treatments of Ti–5Al–5Mo–5V–3Cr Alloy Additively Manufactured by Powder Bed Fusion–Laser Beam

Abstract

The properties of 3D‐printed components via powder bed fusion–laser beam (PBF–LB) depend strongly on the processing parameters, particularly due to the rapid solidification conditions involved. In this study, an innovative post‐treatment strategy combining deep cryogenic treatment (DCT) and thermal aging treatments are introduced to enhance the properties of Ti–5Al–5V–5Mo–3Cr alloy (Ti‐5553) alloy fabricated by PBF–LB. In the results, it is revealed that DCT of as‐built material can refine the grain size and introduce defects and sub‐grain boundaries, thereby improving strength and ductility without significantly altering the microstructure or phase composition. However, applying DCT after aging can significantly improve ductility and maintain strength, primarily by refining β‐phase grains. Conversely, thermal aging followed by DCT of as‐built materials tends to increase strength at the expense of ductility, due to the formation of the ω phase and defects induced by the cryogenic treatment that in turn promote the development of more abundant and finer α phase within grains during aging. In the findings of this research, significant insights and valuable methodologies are offered for optimizing the mechanical properties of Ti‐5553 alloy manufactured by PBF–LB via an extra DCT following thermal aging.