Cryogenic mechanical properties of two Al-Cu alloys processed by laser powder bed fusion

Aluminum-copper alloys, classified as age-hardenable high-strength alloys, that retain high strength and ductility at cryogenic temperatures, unlike many other metals that become brittle. They are preferred in aerospace, rocket propellant tanks, and liquid oxygen/hydrogen containers. However, they exhibit a susceptibility to hot cracking, making them unsuitable for processing, especially for welding or additive manufacturing processes. Despite this reality, the laser powder bed fusion processability of AA2219 and A205 was demonstrated. This achievement is now opening the manufacturing of advanced components to be used in cryogenic service conditions. In this presentation, the as-built and heat-treated microstructure will be presented. The cryogenic mechanical properties, including cryohardness, cryo-tensile, and cryo-instrumented impact testing, were performed for both alloys, and the respective data will be compared. The difference in deformation behavior, based on the starting microstructure and/or heat treatment, will be presented.