Atomic-scale structural evolution and welding deformations of laser welded joints in Ag nanowire connectors on homogeneous substrates

The formation mechanism and the influence of laser power on welding deformations of welded joints in Ag nanowire connectors were investigated using molecular dynamic simulations. Simulation results revealed that some regions of voids in the welded joint were filled due to the heat in the heat affected zone. The laser irradiation with the appropriate power can decrease dislocations and phase transitions generated by cold welding. The welding strength possessed an upward trend with the increase in laser power. With the increase of the laser power, the shear resistance of the welded joint improved. However, the welded joint after the laser with the excessive power weakened. Furthermore, by comparing the laser welding and the thermal annealing welding, we found that the laser welded joint possesses fewer amorphous atoms, phase transitions, dislocations, residual stress, and possibility of the shear deformation via simulation. (author)