Molecular dynamics simulations of intergranular fracture in UO2 with nine empirical interatomic potentials
Molecular dynamics simulations of intergranular fracture in UO2 with nine empirical interatomic potentials
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DOI：
10.1016/j.jnucmat.2014.05.034
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发表时间：
2014-09
影响因子：
3.1
通讯作者：
Yongfeng Zhang;P. Millett;M. Tonks;X. Bai;S. B. Biner
中科院分区：
文献类型：
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作者：
Yongfeng Zhang;P. Millett;M. Tonks;X. Bai;S. B. Biner
采用分子动力学模拟方法，采用双晶体模型研究了UO 2的沿晶断裂行为.研究了< 1 0 0>对称倾斜双晶（{1 1 1}孪晶）晶界和< 1 1 0>对称倾斜双晶（{1 1 1}孪晶）晶界的各向异性断裂行为。九个原子间的势，七个刚性离子加两个核壳的，用来阐明可能的潜在的依赖。裂纹从缺口开始沿沿着扩展，观察到大多数电位。结果表明，1993年边界比1995年边界更容易破裂，这是由与前者相关的较低能量释放率所指示的。然而，一些潜在的依赖性被确定在裂纹尖端的瞬态塑性变形的存在，并讨论了有关的材料性能，包括亚稳相的过剩能量和沿晶断裂的临界能量释放率的结果。在一般情况下，在断裂模拟中观察到局部塑性，预测亚稳相的低过剩能量和晶间断裂的高临界能量释放率的潜力。
The intergranular fracture behavior of UO 2 was studied using molecular dynamics simulations with a bicrystal model. The anisotropic fracture behavior due to the different grain boundary characters was investigated with the< 1 0 0> symmetrical tilt Σ 5 and the< 1 1 0> symmetrical tilt Σ 3 ({1 1 1} twin) grain boundaries. Nine interatomic potentials, seven rigid-ion plus two core–shell ones, were utilized to elucidate possible potential dependence. Initiating from a notch, crack propagation along grain boundaries was observed for most potentials. The Σ 3 boundary was found to be more prone to fracture than the Σ 5 one, indicated by a lower energy release rate associated with the former. However, some potential dependence was identified on the existence of transient plastic deformation at crack tips, and the results were discussed regarding the relevant material properties including the excess energies of metastable phases and the critical energy release rate for intergranular fracture. In general, local plasticity at crack tips was observed in fracture simulations with potentials that predict low excess energies for metastable phases and high critical energy release rates for intergranular fracture.