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arXiv · 2609.06198

Zonal dislocations in Laves phases: A coupled synchro-shear slip mechanism

Sang-Hyeok Lee·Mariano Forti·Thomas Hammerschmidt·Gang Liu·Julien Guénolé·Siyuan Zhang·Gerhard Dehm·Sandra Korte-Kerzel·Zhuocheng Xie
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Abstract

Synchro-shear is the primary plastic deformation mechanism in Laves phases at elevated temperatures, mediated by synchro-Shockley partial dislocations-zonal dislocations that proceed via localized events such as kink-pair nucleation and propagation. Using atomistic simulations, we identified a novel slip mechanism in Laves phases, namely coupled synchro-shear slip, involving the synchronized glide of two synchro-Shockley partial dislocations on adjacent slip planes, leading to the formation of extrinsic stacking faults. High-resolution scanning transmission electron microscopy revealed the extended core structures consistent with coupled synchro-Shockley partial dislocations bounded by extrinsic stacking faults in C15 NbCr2 and their involvement in twinning. These results highlight the critical role of coupled synchro-shear slip in enabling phase transformations between Laves polytypes and in governing twinning behavior, providing new atomistic insight into the kinetic nature of plasticity in topologically close-packed intermetallic phases.

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Sang-Hyeok Lee, Mariano Forti, Thomas Hammerschmidt, Gang Liu, Julien Guénolé, Siyuan Zhang, Gerhard Dehm, Sandra Korte-Kerzel, Zhuocheng Xie. 2026-09-05. Zonal dislocations in Laves phases: A coupled synchro-shear slip mechanism. https://arxiv.org/abs/2609.06198

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