Fracture behavior in 3C/4H-SiC using molecular dynamics simulation

KL Yin and YS Zhong and XL Ma and HC Zhang and LP Shi and XD He, MATERIALS TODAY COMMUNICATIONS, 48, 113517 (2025).

DOI: 10.1016/j.mtcomm.2025.113517

As a third-generation semiconductor material with remarkable development potential, the synthesized monocrystalline SiC materials exhibit various polytypes, resulting in phase boundaries (PBs) that significantly influence mechanical behavior. It is crucial to investigate the atomic- scale fracture behavior of SiC materials containing PBs for the reliability evaluation. In this paper, the fracture behavior of SiC under mode I loading is investigated through molecular dynamics (MD) simulations to explore the underlying toughening mechanisms, focusing on the critical parameters determining fracture behavior: (1) the crack incident angle, and (2) the distance between crack tips and the first PB. Our findings reveal pronounced fracture energy anisotropy with different incident angles. PBs enhance the fracture toughness of 3C/4H-SiC by up to 50 % compared to that of monocrystalline SiC. The toughening mechanisms of 3C/4H-SiC can be summarized as PBs blocking cracks, crack deflection and the formation of zigzag paths in different phases, as well as the propagation of long paths in 4HSiC. Moreover, a ductile-to-brittle transition occurs at the crack incident angle of 50 degrees for 3C/4H-SiC when the distance between crack tips and the first PB is 20 nm. Our current study provides mechanistic insights for fundamentally understanding the toughening of SiC materials with phase boundaries.

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