|About this Abstract
||2023 TMS Annual Meeting & Exhibition
||Alloy Behavior and Design Across Length-Scales: An SMD Symposium Honoring Easo George
||Deformation Mechanisms in Compositionally Complex Polycrystalline CoNiCr-based Superalloys
||Steffen Neumeier, Andreas Bezold, Mathias Goeken
|On-Site Speaker (Planned)
To improve the mechanical properties for high temperature applications of fcc medium-/high-entropy alloys (MEA/HEA) based on CoNiCr, compositionally complex alloys have been developed that are additionally strengthened with L12 structured precipitates.
In this work, deformation mechanism maps are presented for such polycrystalline CoNiCr-based superalloys with high precipitate fractions. Despite their chemical differences, the dominant deformation mechanism in all four investigated alloys transitions from shearing by APB-coupled dislocation pairs to shearing under superlattice stacking fault formation with increasing temperatures and/or decreasing strain-rate. However, the regions of the dominant deformation mechanism varies between the different alloys. Additionally, microtwinning is observed at even higher temperatures and/or lower strain-rates but only in the alloys, in which Al and W are substituted for Ti and Ta.
Accordingly, the influence of segregation processes and the role of small compositional changes on the occurring deformation mechanisms are discussed and potential guidelines for future alloy design are given.
||High-Temperature Materials, High-Entropy Alloys, Mechanical Properties