Xian Fankai, Zhou Jinjie, Lian Xiaofeng, Shen Jinchuan, Chen Yuepeng
School of Mechanical Engineering, North University of China Taiyuan 030051 P. R. China
The Key Laboratory of Industrial Internet and Big Data, China National Light Industry Beijing 100048 P. R. China.
RSC Adv. 2024 Jan 2;14(1):616-625. doi: 10.1039/d3ra07374b.
In this paper, we use molecular dynamics to simulate the crack propagation behavior of gradient nano-grained (GNG) copper models with different grain size gradients, compare the crack propagation rates of different models, and analyze the microstructural changes and the mechanism of crack propagation. The simulation results show that the increase of the grain size gradient of the GNG copper model can improve the fracture resistance of the material, and the crack propagation mode undergoes a transition from brittle propagation along the grain boundaries to the formation of pores at the grain boundaries, and then to ductile fracture along the inclined plastic shear zone. The number of dislocations increases with the grain size gradient, while the crack passivation is more serious, indicating that a larger grain size gradient is more effective in inhibiting crack propagation. The introduction of gradient grain size promotes crack propagation and weakens the plasticity of the material relative to the nano-grained (NG) copper model.
在本文中，我们使用分子动力学模拟具有不同晶粒尺寸梯度的梯度纳米晶（GNG）铜模型的裂纹扩展行为，比较不同模型的裂纹扩展速率，并分析微观结构变化和裂纹扩展机制。模拟结果表明，GNG铜模型晶粒尺寸梯度的增加可提高材料的抗断裂能力，裂纹扩展模式经历从沿晶界脆性扩展到在晶界处形成孔洞，再到沿倾斜塑性剪切带韧性断裂的转变。位错数量随晶粒尺寸梯度增加，而裂纹钝化更严重，表明较大的晶粒尺寸梯度在抑制裂纹扩展方面更有效。相对于纳米晶（NG）铜模型，梯度晶粒尺寸的引入促进了裂纹扩展并削弱了材料的塑性。
