基于离散位错动力学的单晶铜构件拉伸特性研究

A novel 2.5D discrete dislocation dynamics framework was established, and the simulation framework and program coupling discrete dislocation dynamics and finite element model for monocrystalline copper was developed to investigate the dislocation evolution behavior of micro-scaled monocrystalline copper in tension. Based on the coupled model, the uniaxial tensile properties of monocrystalline copper were studied, the characteristic curves of uniaxial tension were analyzed, and the internal stress distributions were obtained. The effect of thickness of monocrystalline copper component on the tensile properties was studied, and the intrinsic mechanism which effected the uniaxial tensile properties was revealed. The results show that the dislocation networks are formed inside the crystal gradually with the increase of external load. The dislocations on the boundary absorb the free dislocations, and make them to form the solid forest dislocation intersections, which causes stress concentration. Comparison between the samples with different thicknesses shows that the dislocations in the thinner monocrystalline copper are much easier captured by the boundaries and the forest dislocation networks, where the lower mobile dislocation density leads to harder mechanical property of the copper sample. The simulation results indicate that the established framework and program can be used to evaluate the tensile properties of monocrystalline copper. Moreover, the reasons for size effects in tension of monocrystalline copper were clarified.