MOLECULAR DYNAMICS SIMULATION OF TENSILE DEFORMATION OF NANOMETER MULTILAYER Cu/Ta MATERIALS

Abstract

In this research, the tensile mechanical properties and microstructure evolution of Cu/Ta nanolayered composites were studied using the molecular dynamics simulation method. By analyzing the tensile stress/strain relationship of Cu/Ta with different interface structures and the movement of dislocations during the stretching process, the deformation mechanism of materials with different interface structures and the effect of interface structures on the tensile strength of Cu/Ta nanolayered composites are revealed. The effect of shear localization during extension is also analyzed. The results show that the dislocation structures at the interfaces of Kurdjumov-Sachs-type and Nishiyama-Wasserman-type samples are parallelogram and triangular interface defect arrays, respectively, which can easily induce two Shockley partial dislocations to slide along different (111) planes, forming an intersection and merging into ladder-rod dislocations. However, dislocations between the Kurdjumov-Sachs š112ć-type sample interfaces exhibit parallel array characteristics, while the interfacial dislocations have non-planar interface components, which can induce deformation twinning. The process is dissociated through a set of intrinsic interfacial dislocations. Shockley partial dislocations are then formed by dislocation motion, creating stacking faults (SF1), and then the second set of partial dislocations may nucleate from the interface and slide on the adjacent SF1 plane, eventually forming deformation twinning.