Dynamic tensile (micro-spallation) fracture and subsequent recompression in a molten state is the key physical process for metallic materials undergoing multiple intense dynamic loadings. However, there still lacks in-depth analysis of the complete evolution process from damage accumulation to recompression, as well as the influence of damage history on subsequent deformation and fracture. In the present work, the mechanism of cooperative competition evolution between the melt-phase and voids has been proposed as a new perspective to investigate damage evolution. Various important physical phenomena discovered in larger-scale MD simulations of molten aluminum can be self-consistently explained according to the proposed mechanism, such as the rate-dependence of spall strength and the pressure oscillation. The recompression-after-damage and second fracture process are discussed in detail to analyze the damage history effect. Under the present framework, two theoretical models have been proposed from the perspective of void and melt-phase evolution, respectively. The proposed models agree well with the simulation results and provide a comprehensive understanding of the damage evolutionary characteristics.

中文翻译：

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微散裂和再压缩过程中熔体相和空隙之间的合作竞争


动态拉伸（微剥落）断裂和随后在熔融状态下的再压缩是金属材料承受多次强烈动态载荷的关键物理过程。然而，目前仍缺乏对从损伤积累到再压缩的完整演化过程以及损伤历史对后续变形和断裂的影响的深入分析。在目前的工作中，提出了熔体相和孔隙之间的协同竞争演化机制，作为研究损伤演化的新视角。在熔融铝的大规模MD模拟中发现的各种重要物理现象可以根据所提出的机制得到自洽的解释，例如剥落强度的速率依赖性和压力振荡。详细讨论了损伤后的再压缩和二次断裂过程，以分析损伤历史效应。在目前的框架下，分别从空洞和熔体相演化的角度提出了两种理论模型。所提出的模型与模拟结果非常吻合，并提供了对损伤演化特征的全面理解。