Shear‐induced amorphization in boron subphosphide (B₁₂P₂): Direct transition versus stacking fault mediation

Abstract

The shear-induced amorphization has been observed in many strong ceramics and is responsible for their cracking and fragmentation. But its underlying mechanism remains elusive due to the complex structure and bonding environment in strong ceramics. To illustrate the deformation mechanism of local amorphization in strong ceramics, we employed molecular dynamics simulations with a deep-learning force field to examine the shear-induced amorphization in B 12 P 2 . Surprisingly, we identified a stacking-fault-mediated amorphization mechanism along the most plausible slip system (1 1 1)/[1 1 2]. This mechanism is even more favorable at a higher temperature than room temperature. In contrast, the direct crystal to amorphization transition, due to the icosahedral slip, is observed for the other most plausible slip system (0 1 1)/[2 1 1]. We report the activation volume and the activation free energy for the amorphization along the (1 1 1)/[1 1 2] slip system. The derived activation volume is only 41.47 A 3 , which is roughly 2-3 icosahedra, suggesting that the localized amorphization in B 12 P 2 is mediated by stacking fault formation. The previous results suggest complex amorphization mechanisms in strong ceramics.

Supercritical CO2‐Induced Amorphization in 2D Materials: Mechanism and Applications

“…In addition, Sun et al. found the shear induced amorphization in NiTi micropillars [48] . The atomic structure changes from B2 phase to martensite twins (B19) under shear stress, which further leads to the formation of stacking faults and partial dislocations near grain boundaries (Figure 14b).…”

“…In addition, Sun et al found the shear induced amorphization in NiTi micropillars. [48] The atomic structure changes from B2 phase to martensite twins (B19) under shear stress, which further leads to the formation of stacking faults and partial dislocations near grain boundaries (Figure 14b). The crystalline defects accumulate near the martensite grain boundaries under large local shear strains, resulting in atomic shuffling and the subsequent amorphization (Figure 14c).…”