About this Abstract |
Meeting |
2025 TMS Annual Meeting & Exhibition
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Symposium
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Mechanical Behavior Related to Interface Physics IV
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Presentation Title |
A large hysteresis behavior in CaFe2As2 single crystal via the Bauschinger effect associated with buckling-induced formation of nanocrystalline structure |
Author(s) |
Alexander Horvath, Juan Schmidt, Daniel Saccone, Christopher R. Weinberger, Paul C. Canfield, Seok-Woo Lee |
On-Site Speaker (Planned) |
Alexander Horvath |
Abstract Scope |
Mechanical behavior of ThCr2Si2-structured intermetallic compounds is of interest because of their giant superelasticity and hysteresis stress-strain behavior via the lattice collapse-expansion mechanism under c-axis compression. Recently, we found that nanoindentation on CaFe2As2 single crystals along a-axis also exhibits a large hysteresis behavior in load-displacement data even without lattice collapse-expansion. Transmission electron microscopy revealed that a nanocrystalline structure is created underneath the indent by local atomic layer buckling and dislocation nucleation. Density Functional Theory calculation confirmed that CaFe2As2 is an anisotropic layered material with a significantly low energy barrier of plastic slip in the (001)/[100] slip system, where dislocations can be easily nucleated. Piled-up dislocations near the newly formed grain boundaries seem to cause the Bauschinger effect (reversed plasticity), leading to hysteresis behavior. Our results strongly suggest that anisotropic layered materials could exhibit hysteresis behavior under nanoindentation along in-plane direction of atomic layers. |
Proceedings Inclusion? |
Planned: |
Keywords |
Thin Films and Interfaces, Characterization, Nanotechnology |