Imperial College London

Professor David W. McComb

Faculty of EngineeringDepartment of Materials

Adjunct Professor



+44 (0)20 7594 6750d.mccomb Website




Royal School of MinesSouth Kensington Campus






BibTex format

author = {Smith, TM and Good, BS and Gabb, TP and Esser, BD and Egan, AJ and Evans, LJ and McComb, DW and Mills, MJ},
doi = {10.1016/j.actamat.2019.04.038},
journal = {Acta Materialia},
pages = {55--65},
title = {Effect of stacking fault segregation and local phase transformations on creep strength in Ni-base superalloys},
url = {},
volume = {172},
year = {2019}

RIS format (EndNote, RefMan)

AB - © 2019 In this study, two similar, commercial polycrystalline Ni-based disk superalloys (LSHR and ME3) were creep tested at 760 °C and 552 MPa to approximately 0.3% plastic strain. LSHR consistently displayed superior creep properties at this stress/temperature regime even though the microstructural characteristics between the two alloys were comparable. High resolution structural and chemical analysis, however, revealed significant differences between the two alloys among active γ′ shearing modes involving superlattice intrinsic and extrinsic stacking faults. In ME3, Co and Cr segregation and Ni and Al depletion were observed along the intrinsic faults - revealing a γ′ to γ phase transformation. Conversely in LSHR, an alloy with a higher W content, Co and W segregation was observed along the intrinsic faults. This observation combined with scanning transmission electron microscopy (STEM) simulations confirm a γ′-to-D019 χ phase transformation along the intrinsic faults in LSHR. Using experimental observations and density functional theory calculations, a novel local phase transformation strengthening mechanism is proposed that could be further utilized to improve the high temperature creep capabilities of Ni-base disk alloys.
AU - Smith,TM
AU - Good,BS
AU - Gabb,TP
AU - Esser,BD
AU - Egan,AJ
AU - Evans,LJ
AU - McComb,DW
AU - Mills,MJ
DO - 10.1016/j.actamat.2019.04.038
EP - 65
PY - 2019///
SN - 1359-6454
SP - 55
TI - Effect of stacking fault segregation and local phase transformations on creep strength in Ni-base superalloys
T2 - Acta Materialia
UR -
VL - 172
ER -