|About this Abstract
||2023 TMS Annual Meeting & Exhibition
||Advanced Characterization of High-temperature Alloys: Phase Evolution during Manufacturing and Service-induced Deformation
||Segregation-assisted Yield Strength Anomalies in Superalloys
||Steffen Neumeier, Andreas Bezold, Mathias Goeken
|On-Site Speaker (Planned)
In the past decade, the significance of segregation of alloying elements to defects during high temperature deformation of superalloys strengthened by L12 precipitates became evident. Previous investigations revealed that segregation processes facilitate shearing of the ordered phase by lowering defect energies causing softening.
Here we show that segregation-assisted processes can also induce an anomalous increase in the yield strength of Co- and CoNi-base superalloys. By facilitating the dissociation of dislocations at the matrix/precipitate interfaces in combination with an atomic-scale reordering process of the resulting planar defects, these processes cause an impediment of low temperature shearing mechanisms. This leads to a transition of the operating deformation mechanism and the observed strengthening effect. Our results unravel the elementary mechanisms why the transition to stacking fault shearing does not necessarily cause softening. Furthermore, the significance of segregation on the operating deformation mechanisms is revealed which can guide alloy design of novel superalloys.
||High-Temperature Materials, Mechanical Properties, Copper / Nickel / Cobalt