About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
|
Symposium
|
Phase Transformations and Microstructural Evolution
|
Presentation Title |
Phase Transformations during Cryogenic Treatment of Additively Manufactured Nitrogen Atomized 17-4PH Stainless Steel |
Author(s) |
James Zuback, Fan Zhang |
On-Site Speaker (Planned) |
James Zuback |
Abstract Scope |
Additively manufactured nitrogen atomized 17-4PH stainless steel retains significant amounts of austenite after heat treatments that are intended to produce a fully martensitic material. Interstitial nitrogen reduces the martensite transformation temperature below room temperature, leading to an incomplete transformation. Conventional metallurgical practices involve cooling to cryogenic temperatures to complete the transformation of residual austenite to martensite. Here, the phase transformations of nitrogen atomized 17-4PH stainless steel during cryogenic cooling are investigated by in-situ synchrotron X-ray diffraction and magnetometry. Alloys with variations in chemical composition are cooled from the as-built and heat-treated conditions to probe the effects of chemistry and austenite stability of phase transformation kinetics. Both the amount and rate of transformation depend on the initial alloy composition and heat treatment condition. Further, the transformation mechanism in the additively manufactured materials is shown to be isothermal, as opposed to the athermal mechanism commonly observed in wrought 17-4PH. |
Proceedings Inclusion? |
Planned: |
Keywords |
Additive Manufacturing, Phase Transformations, Iron and Steel |