Grain-size-dependent microstructure effects on cyclic deformation mechanisms in CoCrFeMnNi high-entropy-alloys. (15th March 2022)

• Record Type: Journal Article
• Authors: Luo, Mao-Yuan; Lam, Tu-Ngoc; Wang, Pei-Te; Tsou, Nien-Ti; Chang, Yao-Jen; Feng, Rui; Kawasaki, Takuro; Harjo, Stefanus; Liaw, Peter K.; Yeh, An-Chou; Lee, Soo Yeol; Jain, Jayant; Huang, E-Wen
• Is Part Of: Scripta materialia. Number 210(2022)
• Publication Date: 2022-03-15
• Subjects: High-entropy alloy -- Grain size -- Low-cycle fatigue -- Deformation twins -- Neutron-diffraction; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2021.114459
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The effect of grain size on strain-controlled low-cycle fatigue (LCF) properties in the CoCrFeMnNi high-entropy alloys (HEAs) was investigated towards the distinct microstructural developments during cyclic loading at a strain amplitude of ± 1.0%. A much more prominent secondary cyclic hardening (SCH) behavior at the final deformation stage was observed in the fine-grained (FG, 18 µm) than in the coarse-grained (CG, 184 µm) CoCrFeMnNi. In-situ neutron-diffraction and microscopic examination, strongly corroborated by molecular dynamic (MD) simulations, indicated that dislocation activities from planar slip to wavy slip-driven subgrain structures within the grains acted as the primary cyclic-deformation behaviors in the FG CoCrFeMnNi. Differently observed in the cyclic behavior of the CG CoCrFeMnNi was due to a transition from the planar dislocation slip to twinning. Our findings suggested that the fatigue-resistant HEAs can be designed via tuning the microstructure with an optimal range of grain size at a specific strain amplitude. Graphical abstract: Image, graphical abstract