[T19] High Entropy Alloys

[14D-T19-06] Hetero-Deformation-Induced (HDI) Softening of a Harmonic Structure Designed CrMnFeCoNi Alloy Compact at Elevated Temperatures

*H. Kawano¹, S. Hosogi¹, M. Kawabata², H. Fujiwara³, K. Ameyama³ (1.Graduate school, Ritsumeikan University, Japan, 2.Ritsumeikan Global Innovation Research Organization, Japan, 3.College of Science and Engineering, Ritsumeikan University, Japan)

Keywords:HDI softening, stress partitioning, compression test, strain rate sensitivity, pseudo-superplasticity

Hetero-Deformation-Induced (HDI) strengthening is the important key to the strengthening mechanism
in heterogeneous structure materials that exhibit both strength and ductility simultaneously. In the
Harmonic Structure (HS) materials, high strength and high ductility are also simultaneously exhibited in
the same manner via the HDI strength at room temperature. In the present study, a high entropy
CrMnFeCoNi alloy with homogeneous and harmonic structures were subjected to high temperature
compression tests at different strain rates. As a result, the HS designed specimen showed a significant
reduction in flow stress compared to the homogeneous structure counterpart. In addition, the
homogeneous specimens had a strain rate sensitivity value of less than 0.3, while the HS specimens had a
strain rate sensitivity value greater than 0.3, such as 0.541 at 1173K. In other words, the HS specimens
exhibited pseudo-superplastic deformation, i.e. Hetero-Deformation-Induced (HDI) softening.