About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
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Symposium
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Deformation Mechanisms, Microstructure Evolution, and Mechanical Properties of Nanoscale Materials
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Presentation Title |
Grain Size Refinement Altering Yielding Mechanism in an Ultrafine-grained High-Mn Austenitic Steel |
Author(s) |
Chang-Yu Hung, Yu Bai, Tomotsugu Shimokawa, Ya-Peng Yu, Nobuhiro Tsuji, Mitsuhiro Murayama |
On-Site Speaker (Planned) |
Chang-Yu Hung |
Abstract Scope |
Some ultrafine-grained (UFG) metals have been found to overcome the paradox of strength and ductility. An UFG high-Mn austenitic steels is one of these and exhibits a unique macroscopic discontinuous yielding behavior. This presentation will address the underlying mechanism of discontinuous yielding behavior using ex/in-situ deformation TEM and dislocation analyses. We experimentally revealed that the plastic deformation mechanisms around macroscopic yield point show a prominent association with grain size. The main mechanism shifts from conventional slip in grain interior to twinning nucleation from grain boundaries by decreasing grain size to less than 1μm. The atomistic insights of dislocation reaction into twinning nucleation at the dominant type of GB (sigma3 boundary) were detailed. Expressly, the twin boundary having Shockley partial dislocations with disconnection character acts as a preferential twin nucleation site, that is characteristically different from coarse-grained counterparts and is likely ascribed to the lack of interior dislocation activities in UFG. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, Iron and Steel, Mechanical Properties |