Abstract The underlying micromechanism remains to be clarified for the bulk inelastic behaviour of specific ceramics under impact loads. In this study, the silicon carbide materials were subjected to the split-Hopkinson pressure bar compression in which the strain rate was not constant but increased to the dynamic level at high stresses. The inelastic deformation occurs in the high strain rate stage in compression, followed by the final transgranular fracture. The post-test fragments were examined in both the SEM and high resolution TEM. It was found that macroscopic inelastic behaviour is dominated by the dislocation motion and the localised amorphisation that arise at high strain rates. The damage and thus the degraded modulus in the dynamic inelastic deformation were incorporated to modify a dynamic fragmentation model to evaluate the fragment size as a function of strain rates. The modified model more accurately predicts the size of fragments produced at high strain rates.

中文翻译：

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碳化硅动态压缩非弹性变形微观机制及修正破碎模型

摘要 特定陶瓷在冲击载荷下的整体非弹性行为的潜在微观机制仍有待阐明。在这项研究中，碳化硅材料经受分裂霍普金森压力棒压缩，其中应变率不是恒定的，而是在高应力下增加到动态水平。非弹性变形发生在压缩的高应变率阶段，然后是最终的穿晶断裂。测试后的碎片在 SEM 和高分辨率 TEM 中进行了检查。发现宏观非弹性行为由位错运动和高应变率下出现的局部非晶化支配。结合动态非弹性变形中的损伤和降低的模量来修改动态破碎模型，以评估作为应变率函数的碎片大小。修改后的模型更准确地预测了在高应变率下产生的碎片的大小。