Quasi-continuum Simulations of Solid-state Pressure Nanowelding of Metals

Abstract

Background: Nanowelding is an attractive bottom-up fabrication technique that allows the construction, connection, and repair of nanomaterials. The effects of contact interference, crystal orientation, and material type of nanoscale welded pairs are investigated in terms of atomic trajectories, strain distribution, and the stress-strain curve. Methods: The quasi-continuum (QC) method is applied to simulate nanowelding process. The QC method is a multi-scale combined molecular dynamics approach that mixes atomistic and continuum algorithms. Results: At a small contact interference of 0-1 nm, the ultimate stress of welded pairs is independent of the magnitude of contact interference. Regarding the effect of material type, the average ultimate stress for Ni-Ni welded pairs is the highest and that for Cu-Cu welded pairs is the lowest, regardless of the contact orientation mode. The elongation of Ni-Ni welded pairs increases with increasing contact interference. Conclusion: The crystal orientation of the contact plane and material type significantly determine the welding quality. Welding on the close-packed plane of both substrates leads to the highest ultimate stress. The ultimate stress for Ni-Ni welding pairs is the highest, and that for Cu- Cu welded pairs is the lowest.