|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Advanced Real Time Optical Imaging
||Determining Metastable Phase Transformation Temperature between Al4Sm-beta and Al4Sm-gamma
||Shihuai Zhou, Xiong Yang, Fanqiang Meng, Ryan T. Ott, Matthew J. Kramer, Ralph E. Napolitano
|On-Site Speaker (Planned)
It is challenge to control the phase transformation between metastable phases before they transfer into stable phases. In this work, we investigate the metastable phase transformation between Al4Sm-gamma and Al4Sm-beta using SEM, In-situ XRD, DSC and EPMA. The as-cast Al-20 at%Sm alloy comprised of the beta phase was treated at different temperatures. The beta to gamma phase transformation was observed below 877.8K. To determine phase transformation temperature accurately, the real time images of the diffraction pattern during heating were collected using synchrotron high-energy XRD and the associated crystal structures were characterized. The invariant phase transformation temperature(beta<=>gamma) was confirmed to be 911 K. Therefore, the metastable phase transformation between beta and gamma is maneuverable. With the Gibbs free energy of the beta phase in literature, temperature (beta<=>gamma) and the first-principles data, the thermodynamic parameters of the gamma phase were evaluated and the metastable phase diagram was calculated.
||Planned: Supplemental Proceedings volume