|About this Abstract
||2023 TMS Annual Meeting & Exhibition
||Advanced Characterization of High-temperature Alloys: Phase Evolution during Manufacturing and Service-induced Deformation
||Creep Assisted Phase Transformation Deformation Mechanisms in Polycrystalline Ni-based Superalloys and Their Impact on the Creep Performance
||Daniel Barba, Ashton J. Egan, Satoshi Utada, Yilun Gong, Yuanbo Tang, Veronika Mazanova, Michael J. Mills, Roger C. Reed
|On-Site Speaker (Planned)
In-service creep deformation in polycrystalline Ni-based superalloys is controlled by the formation of a rich variety of complex shearing faults forming at the core of the γ' phase. The lengthening and thickening rate of these faults depends on an intriguing combination of dislocation interactions and diffusional processes of the alloy elements at the core of the fault. The effect of alloy composition on this process is still not fully understood. In this work, cutting edge correlative HR-TEM and EDX spectroscopy is used to study the deformation mechanisms of three different Ni-based superalloys with carefully designed ratios of disordering-to-ordering promoting elements (Co-Cr against Nb-Ta-Ti). The results shows that additions of ordering promoting elements reduce the diffusional processes required for the faults to lengthen thus reducing the creep rates for higher Nb-Ta-Ti alloys. These insights provide a path to follow in the design of improved grades of creep-resistant polycrystalline alloys beyond 700°C.
||High-Temperature Materials, Phase Transformations, Other