A physical-based constitutive model considering the motion of dislocation for Ni3Al-base superalloy

Abstract

Ni3Al-base superalloys are widely used as high temperature structure materials in aerospace applications. In order to study the microphysical mechanism of Ni3Al-base superalloys, unidirectional tension tests are carried out on IC10 (a typical Ni3Al-base superalloy in China) at 300 K and 973 K with a strain rate 1 × 10−3 s−1 in the direction of [001]. Different strain levels (0.8% strain, 3.0% strain, 6.0% strain and 8.2% strain) are tested and the dislocation configurations under these different deformation conditions are observed by transmission electron microscope (TEM). Both edge dislocation and screw dislocation are found in the late stage of deformation. The effect of different types of dislocation on deformation has been investigated through measuring the dislocation densities. Based on the experimental results, a new physical-based constitutive model has been established by considering the effects of dislocation movement. The evolution forms for edge-character dislocation and screw-character dislocation are studied respectively in each slip system. The laws of latent hardening between different slip systems are considered directly. Finally, the model has been implemented in a crystal plasticity finite element method numerical framework. And, the simulated results at 300 K and 973 K with a strain rate 1 × 10−3 s−1 show good qualitative agreement with experimental results.