E-Wen Huang¹, Che-Wei Tsai², An-Chou Yeh², Soo Yeol Lee³, Stefanus Harjo⁴, Peter K. Liaw⁵, Tu-Ngoc Lam¹, You-Shiun Chou¹; ¹National Chiao Tung University, ²National Tsing Hua University, ³Chungnam National University, ⁴J-PARC Center, Japan Atomic Energy Agency, ⁵University of Tennessee

Two equal-molar, face-centered-cubic, high-entropy alloy systems are measured by in-situ neutron-diffraction experiments subjected to continuous tension-compression cyclic loading at room temperature. With spallation neutron, the evolutions of multiple diffraction peaks are collected simultaneously in the axial loading direction and radial direction of the cylindrical dog-bone specimen for lattice-strain measurement and peak profile analysis. Recorded temperature variations during fatigue cycles are compared with the thermodynamics-model predictions based on lattice structural changes. The discrepancy between the modeled and measured temperature evolution indicates the evolution of the microstructure during fatigue deformation, which is validated from the microscopic examination.