Temperature effects on the transition from Lomer-Cottrell locks to deformation twinning in a Ni-Co-based superalloy

Deformation mechanisms of a Ni-Co-based superalloy at various temperatures were investigated with aberration corrected and conventional transmission electron microscopes. When deformed at intermediate temperature, Lomer-Cottrell locks were formed in primary gamma' precipitates in this superalloy; at high temperatures, however, microtwins become prominent. The transition from Lomer-Cottrell locks to microtwins with temperature increase is discussed, in particular, on the reordering process in the ordered gamma' precipitates during the deformation twinning. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.