Atomistic study of crack growth behavior in crystalline Mg/amorphous Mg-Al nanocomposites
Atomistic study of crack growth behavior in crystalline Mg/amorphous Mg-Al nanocomposites
复制标题
晶态镁/非晶态镁铝纳米复合材料裂纹扩展行为的原子研究
DOI：
10.1016/j.commatsci.2015.09.023
复制
发表时间：
2016
影响因子：
3.3
通讯作者：
Li Y. L.
中科院分区：
文献类型：
--
作者：
Song H. Y.;Li Y. L.
采用分子动力学模拟方法研究了晶界间距和晶体取向对晶态/非晶态（C/A）Mg/Mg-Al纳米复合材料拉伸裂纹扩展行为的影响。考虑了三种不同初始裂纹晶向的试样。结果表明，尽管两种含裂纹试样都表现出塑性，但其变形机制却截然不同。对于CB间距较大的试样A和C，形变孪晶和新晶粒的形核与长大主导裂纹塑性变形。对于CB间距较小的试样A和B，位错和界面滑移是裂纹顶端的重要塑性变形模式。而小间距试样C的裂纹塑性变形主要由相邻晶相区新晶粒的形核和长大引起。本文还对C/A Mg/Mg-Al纳米复合材料的上述裂纹变形行为进行了分析。研究结果为高性能六方密排金属及合金材料的设计提供了依据。
The effects of crystalline boundary (CB) spacing and crystal orientation on the crack propagation behavior in crystalline/amorphous (C/A) Mg/Mg–Al nanocomposites under tensile loading are investigated using molecular dynamics simulation method. Three samples with different crystal orientations of initial crack are considered. The results show that although both samples with cracks exhibit plasticity, the deformation mechanisms are drastically different. For samples A and C with larger CB spacing, the deformation twinning and the nucleation and growth of new grain dominate the crack plastic deformation. For samples A and B with smaller CB spacing, the dislocation and interfacial slip are important plastic deformation mode at crack top. However, the crack plastic deformation of sample C with small CB spacing is mainly induced by the nucleation and growth of new grain in neighbor crystalline phase sections. The above mentioned crack deformation behaviors of C/A Mg/Mg–Al nanocomposites are also disclosed and analyzed in present work. The results here provide a strategy for the design of high-performance hexagonal-close-packed metal and alloy materials.