About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
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Symposium
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High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond II
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Presentation Title |
The Cyclic Plastic Strain Localization and the Fatigue Crack Initiation in Equiatomic CrCoNi Medium-entropy Alloy |
Author(s) |
Veronika Mazanova, Milan Heczko, Connor Slone, Shih Mulaine, Easo P. George, Maryam Ghazisaeidi, Jaroslav Polak, Michael J. Mills |
On-Site Speaker (Planned) |
Veronika Mazanova |
Abstract Scope |
Multi-principal-element alloys became a topic of significant interest thanks to their outstanding mechanical properties at room and low temperatures. However, there is still a lack of information about their fatigue properties. In current work, the attention is focused on model system, equiatomic CrCoNi alloy in fully recrystallized microstructural state which combines good cyclic strength with superior resistance to cyclic plastic deformation. The cyclic plastic localization and its role in the fatigue crack initiation during low cycle fatigue loading were studied. A sophisticated experimental workflow was designed to extract information from the surface and the bulk of tested material using a combination of SEM, EBSD, ECCI, FIB, and HR-STEM. High fraction of annealing twin and the fatigue-induced deformation twin boundaries were preferential sites for localized cyclic plastic strain. Moreover, stress concentrations near deformation twins led to activation of TWIP and TRIP plasticity and early, well-development of surface relief. |