Microsegregation of Alloying Elements at Deformation-Induced Stacking Faults in a Powder Metallurgy Nickel-Base Superalloy

Article Materials Science, Multidisciplinary

Local Phase Transformation Strengthening at Microtwin Boundaries in Nickel-Based Superalloys

A. J. Egan et al.

Summary: This study investigates the effect of Nb content on local phase transformation strengthening during high temperature creep in two similar polycrystalline alloys. The results show that the alloy with higher Nb content exhibits superior creep strength. Characterization of the deformation microstructures and density functional theory calculations reveal that a novel local phase transformation along microtwin interfaces plays a key role in enhancing the creep strength.

ACTA MATERIALIA (2022)

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Article Materials Science, Multidisciplinary

Dynamic localized phase transformation at stacking faults during creep deformation and new criterion for superalloy design

Longsheng Feng et al.

Summary: This article reviews the recent experimental observations, thermodynamic analysis, first-principles calculations, and computational tools and databases related to dynamic localized phase transformation (LPT) in high-temperature alloys. The generality of the LPT phenomenon, challenges in quantitative predictions of LPT, LPT-strengthening and LPT-softening, as well as opportunities offered by the LPT mechanism in the design of the next generation of alloys are discussed.

MRS COMMUNICATIONS (2022)

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Article Materials Science, Multidisciplinary

Enhanced creep performance in a polycrystalline superalloy driven by atomic-scale phase transformation along planar faults

Lola Lilensten et al.

Summary: This study investigates the differences in creep behavior of polycrystalline Ni-based superalloys with two different Nb contents, attributing the mechanical performance variation to phase transformations along planar faults. The presence of stacking faults and their composition in the alloys are analyzed using electron channeling contrast imaging and atom probe tomography, revealing insights into the underlying mechanisms of creep strain rate differences. The findings suggest a potential atomic-scale driven alloy design approach for enhancing creep resistance by promoting local phase transformations along planar faults at 750 degrees C.

ACTA MATERIALIA (2021)

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Article Materials Science, Multidisciplinary

Utilizing local phase transformation strengthening for nickel-base superalloys

Timothy M. Smith et al.

Summary: Research has shown that local phase transformations at superlattice stacking faults contribute to a threefold improvement in creep strength in a nickel-based superalloy. By calculating energy differences and their dependence on composition, researchers can better guide the optimization of strengthening mechanisms for alloys.

COMMUNICATIONS MATERIALS (2021)

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Article Metallurgy & Metallurgical Engineering