|About this Abstract
||2023 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||H-20: Residual Stress Mitigation via Cryogenic Temperature Induced Martensitic Phase Transformation in Stainless Steels
||John Chrystal, Richard Moat
|On-Site Speaker (Planned)
Via the Artemis missions, NASA plans to establish a permanent lunar base at the moon’s south pole. Additive Manufacturing will be used heavily for this. A known problem with AM metals is high tensile residual stress causing deleterious effects. Furthermore, in this lunar context, conventional stress mitigation methods via heat treatment are unlikely to be viable due to energy constraints. However, exposure to the naturally cryogenic temperatures in the permanently shadowed craters at the lunar south pole can drive phase transformation in some stainless steels. In 304 stainless steels, the austenite stabilizing alloying elements are at sufficient levels that limited martensitic phase transformations only begin below -120 Celsius. This solid-state martensitic transformation generates compressive stress locally around it. This martensitic compressive stress acts to counterbalance the tensile manufacturing stress, thus acting as a novel residual stress mitigation technique that could be used for lunar and space applications.
||Phase Transformations, Iron and Steel, Additive Manufacturing