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<p>The deformation behaviors of single-crystal 3C-SiC containing spherical voids under uniaxial compression are investigated using molecular dynamics simulations. Unlike prior studies focused on metallic systems or SiC under tension and nanoindentation, this work systematically examines the effects of void size, volume fraction, and spatial arrangement on dislocation-driven plasticity in porous 3C-SiC. The results show that void surfaces serve as primary dislocation sources, with 1/2 &lt; 110 &gt; perfect dislocations dominating plastic deformation. For a fixed void volume fraction, the critical stress for dislocation nucleation decreases with increasing void size, consistent with continuum elasticity predictions. For a fixed void size, increasing the void volume fraction reduces both the Young's modulus and the critical stress; however, the critical strain exhibits a non-monotonic trend due to a transition from stress concentration enhancement to stress shielding at high volume fraction. Notably, the spatial arrangement of voids relative to the loading direction critically influences the onset of plasticity: perpendicular alignment promotes earlier dislocation nucleation and stronger void-void interactions compared to parallel alignment. Post-yield deformation is characterized by sustained dislocation activity without macroscopic fracture within the simulated strain range, highlighting the role of voids in promoting plastic deformation and toughening under compression. These findings provide new insights into the deformation mechanisms of porous 3C-SiC, offering microstructure-sensitive design guidelines for SiC-based porous ceramics.</p>

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Effects of void size and volume fraction on mechanical response of 3C-SiC

  • 期刊论文

  • 发表日期：

    2026年5月29日

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  • Sha Sun,
  • Shumin Wang,
  • Tao Li,
  • Yajie Guo

摘要

The deformation behaviors of single-crystal 3C-SiC containing spherical voids under uniaxial compression are investigated using molecular dynamics simulations. Unlike prior studies focused on metallic systems or SiC under tension and nanoindentation, this work systematically examines the effects of void size, volume fraction, and spatial arrangement on dislocation-driven plasticity in porous 3C-SiC. The results show that void surfaces serve as primary dislocation sources, with 1/2 < 110 > perfect dislocations dominating plastic deformation. For a fixed void volume fraction, the critical stress for dislocation nucleation decreases with increasing void size, consistent with continuum elasticity predictions. For a fixed void size, increasing the void volume fraction reduces both the Young's modulus and the critical stress; however, the critical strain exhibits a non-monotonic trend due to a transition from stress concentration enhancement to stress shielding at high volume fraction. Notably, the spatial arrangement of voids relative to the loading direction critically influences the onset of plasticity: perpendicular alignment promotes earlier dislocation nucleation and stronger void-void interactions compared to parallel alignment. Post-yield deformation is characterized by sustained dislocation activity without macroscopic fracture within the simulated strain range, highlighting the role of voids in promoting plastic deformation and toughening under compression. These findings provide new insights into the deformation mechanisms of porous 3C-SiC, offering microstructure-sensitive design guidelines for SiC-based porous ceramics.