|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Coupling Experiments and Modeling to Understand Plasticity and Failure
||New Observations of Phase Transformations during Deformation in Superalloys and High Entropy Alloys: Modeling
||Changning Niu, Carlyn LaRosa, You Rao, T. M. Smith, Jiashi Miao, M. J. Mills, Maryam Ghazisaeidi
|On-Site Speaker (Planned)
This presentation complements experimental observations of phase transformation in Ni base alloys by M. Mills and colleagues. First, we use DFT calculations to study the phase stability of the equiatomic NiCoCr to understand the formation of fine-scale hcp laths observed in experiments. We find that the hcp phase is energetically more favorable against the fcc phase at low temperatures. Atomistic modeling on surrogate systems reveals shearing mechanisms that create the secondary hcp phases. In addition, we study the segregation of common alloying elements to planar faults in γ'-Ni3Al and find no significant driving force for segregation to existing SISF, SESF or twin boundaries, in contrast to the experimental observations. This apparent discrepancy indicates that these faults do not form directly in the γ'-Ni3Al. Instead, their formation involves precursors that are attractive to solutes. This joint effort emphasizes the importance of coupling experiments and theory to characterize and explain deformation mechanisms.
||Planned: Supplemental Proceedings volume