Strength and plastic deformation behavior of nanolaminate composites with pre-existing dislocations
Strength and plastic deformation behavior of nanolaminate composites with pre-existing dislocations
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DOI：
10.1016/j.commatsci.2017.06.016
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发表时间：
2017-10
影响因子：
3.3
通讯作者：
Mohsen Damadam;S. Shao;I. Salehinia;I. Mastorakos;G. Ayoub;H. Zbib
中科院分区：
文献类型：
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作者：
Mohsen Damadam;S. Shao;I. Salehinia;I. Mastorakos;G. Ayoub;H. Zbib
预存位错（PED）普遍存在于晶格中，进而影响屈服应力和塑性变形过程。因此，理解位错运动和相互作用的开始对于修改或设计具有先进性能的新材料至关重要，以便它们的力学行为接近现实条件。一个这样的新材料家族是陶瓷/金属纳米层压材料。在这项工作中，我们已经研究了预先存在的位错的NbC/Nb纳米叠层的力学行为的影响，使用分子动力学模拟。在从3 nm NbC/7 nm Nb样品的应力-应变曲线的不同应变卸载后，我们能够在层内产生具有各种预先存在的位错密度的结构。在两个不同的温度（10 K和300 K）平行于界面的单轴载荷进行每个结构。此外，屈服轨迹确定在300 K下，通过施加双轴面内加载，并与一个通用的流动潜力，用于宏观分析。最后，研究了在沿着两个不同的面内加载方向上存在位错的结构的拉压不对称性。
Pre-existing dislocations (PED) are ubiquitous inside crystalline lattices which in turn affect the yield stress and the process of plastic deformation. Hence, understanding the onset of dislocations motion and interaction is critical in modifying or designing new materials with advanced properties so that their mechanical behavior approach realistic conditions. One such family of new materials is the ceramic/metallic nanolaminates. In this work, we have investigated the effect of pre-existing dislocations on the mechanical behavior of NbC/Nb nanolaminates using molecular dynamics simulations. Upon unloading at different strains from stress-strain curve of 3 nm NbC/7 nm Nb sample, we were able to generate structures with various pre-existing dislocation densities inside the layers. Uniaxial loadings parallel to the interface at two different temperatures (10 K and 300 K) were performed on each structure. Also, the yield locus was determined at 300 K by applying biaxial in-plane loading and fitted with a general flow potential to be used in macroscale analysis. Finally, the tension-compression asymmetry (TCA) was investigated for the structures with pre-existing dislocations along two different in-plane loading directions.