|About this Abstract
||2020 TMS Annual Meeting & Exhibition
||Innovations in High Entropy Alloys and Bulk Metallic Glasses: An SMD & FMD Symposium in Honor of Peter K. Liaw
||Metastability Engineering in Aged Non-equiatomic High Entropy Alloys with Heterogenous Structure Towards Superior Strength-ductility Synergy
||Cheng Zhang, Chaoyi Zhu, Xin Wang, Fan Ye, Kevin Kaufman, Penghui Cao, Xiaoqing Pan, Julie Schoenung, Kenneth Vecchio, Enrique Lavernia
|On-Site Speaker (Planned)
A new class of aged non-equiatomic FeNiCoAl-based high entropy alloys with heterogeneous structure is introduced, which exhibits superior mechanical properties through metastability engineering. In the current alloy system, the formation of B2 (NiAl) particles along high-angle grain boundaries promotes the nucleation of a martensite phase. In addition, stress-induced BCT-structure martensite with a high density of nano-scale twins can form, depending on the composition change of the matrix and the precipitation of γ’ nano-scale particles. The formation of stress-induced martensite is the result of metastability engineering through controlling the martensite start temperature and critical stress. The back-stress strengthening mechanism, unique to the deformation of a heterogeneous microstructure, is verified through mechanical testing, EBSD-based GND density analysis, and TEM analysis. This study confirms the existence of back-stress in precipitation-strengthened alloys with heterogeneous structure, which provides a new strengthening strategy for HEAs. This work also expands the domain of metastability engineering in HEAs.
||Planned: Supplemental Proceedings volume