The effect of Ta, W, and Re additions on the tensile-deformation behavior of model Ni-based single-crystal superalloys at intermediate temperature

Abstract

The influence of refractory additions on tensile deformation behavior has been studied at an intermediate temperature (760°C) using scanning and transmission electron microscopy. Tensile experiments revealed that elemental additions of tantalum (Ta), tungsten (W), and rhenium (Re) could improve the yield strength (YS) of the model alloys with an order of YS(Ni–Al–W) > YS(Ni–Al–Ta) > YS(Ni–Al-Re) > YS(Ni–Al). During the plastic deformation of model alloys at the intermediate temperature, the deformation via Orowan bypassing and shear could be activated synergistically. The changes of anti-phase boundary (APB) energies on {001} and {111} planes are related to the cross-slip driving force, critical resolved shear stress and stage II work hardening rate in γ' precipitates. The effects of γ' size and refractory additions (Ta, W, and Re) on the yield strength of model alloys at intermediate temperature are also discussed, which can provide qualitative reference for alloy design.