Effect of temperature on welding of metallic nanowires investigated using molecular dynamics simulations

Abstract

The mechanism of welding of Au-Au, Ag -Ag and Au -Ag nanowires (NWs) with head-to-head contact is studied using molecular dynamics simulations based on the second-moment approximation of the many-body tight-binding potential. The effect of temperature in the range of 300-900 K is investigated. Simulation results show that at the initial welding, an incomplete jointing area forms through the interactions of the van der Waals attractive force, and that the jointing area increases with increasing the extent of contact between the two NWs during the welding process and temperature. Few defects form along the (1 1 1) close-packed plane during the welding process because the acting stress is quite low. Among the three NW pairs, the Au -Au NWs have the best cold-welding quality, whereas the Au-Ag NWs have the worst coldwelding quality due to the welding of different materials. With an increase in temperature, the weld stress and the mechanical strength of the NWs significantly decrease, and the number of disordered structures increases. The welding fails when the temperature exceeds the molten temperature of the NWs.

Cold welding behavior of metallic glass nanowires: Insights from large-scale numerical simulations

“…2, which plots the evolution of the velocity of the left MGNW with time. The welding and stretching velocity of the MGNW are higher than that used in experiments [1] but universal for MD simulations according to previous works [4,34,37].…”

“…Similarly, an increase in temperature results in the decrease in the ultimate tensile strength (i.e., peak stress during the tensile test), resulting from the much higher kinematic of atoms. Previously, researchers have described similar phenomena in the cold welding process of traditional crystalline metal [37].…”

“…To evaluate the quality of cold welding, the ratio of weld strength R ws was calculated [37]: R ws = r b / r or .r b is the peak stress of the welded MGNWs during the stretching process and r or is the original strength of MG with the same size and loading environment. A larger value of R ws means a better weld quality [34].…”

Molecular dynamics simulations of cold welding of nanoporous amorphous alloys: effects of welding conditions and microstructures

“…For example, Ishida et al 7 demonstrated a pressure of 3.8 GPa to cold weld Au nano-tips. Wu et al 62 cold welded the pairs of Ag–Ag, Ag–Au and Au–Au nanowires, and the applied pressure varies from ∼0.1 to 0.35 GPa. In our previous study, 12 we successfully cold-welded nanocrystalline Au composites by applying loads ranging from ∼0.5 to 1.8 GPa.…”

Nanoscale Assembly of Copper Bearing-Sleeve via Cold-Welding: A Molecular Dynamics Study

“…From then on, cold-welding has been considered as the burgeoning bottom-up nanofabrication and nanoassembly techniques with great promise. In recent years, most studies focused on the cold-welding mechanism considering various material phases [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ], welding conditions [ 15 , 16 ] and joining procedures [ 17 , 18 ].…”