Affiliation：Graduate School of Engineering Science, Osaka University
Abstract：In this work, a chemical short-range order related concept "history-dependent generalized stacking fault energy" (HD-GSFE) was proposed. This concept was demonstrated by utilizing the recent novel multi-principal high-entropy alloy (HEA) with different chemical short-range order levels using a neural network interatomic potential. To demonstrate the impacts of the history dependence and slipping interlayer coupling effect on the GSFE of CSRO HEAs, HD-GSFEs were computed for different shear deformation pathways of the MEAs with different CSRO levels, such as interlayer multiple-time slipping, twin growth, and γ-ε (FCC-HCP) phase transformation. The multiple-time slipping induces CSRO collapse, leading to local shear softening owing to the history dependency of GSFE. Additionally, the slip of neighbouring atomic interlayers is affected by the slipping resulting from the induced CSRO collapse of present interlayers because of the interlayer coupling effect of GSFE. Eventually, by employing a novel kinetic Monte Carlo simulation method based on dislocation/disconnection loop nucleation events and using the HDML-GSFE with the history dependency and interlayer coupling effect, we proposed a laminated micro-substructure evolution that involves twinning and γ-ε phase transformations subject to a finite shear strain rate and finite temperature which is tunable by controlling the chemical short-range order in such high-entropy alloys.
Posted : March 01,2021