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

A bearing is an important component in contemporary machinery and equipment, whose main function is to support the mechanical rotator, reduce the friction coefficient during its movement, and guarantee the turning accuracy. However, assembly of a nanoscale bearing and sleeve is a challenging process for micro-nano mechanical manufacturers. Hence, we show the cold-welding mechanism of a copper nanobearing-nanosleeve via molecular dynamic simulations. We demonstrate that it is feasible to assemble a bearing and sleeve at the nanoscale to form a stable mechanism. The effect of temperature in the range of 150 to 750 K is investigated. As the temperature rises, the mechanical strength and the weld stress of the welded structures markedly decrease, accompanied by the observation of increasing disorder magnitude. This comparison study is believed to facilitate future mechanical processing and structural nano-assembly of metallic elements for better mechanical performance.

Molecular dynamics study on cold-welding of 3D nanoporous composite structures.

Nanoporous metals are a class of novel nanomaterials with potential applications in many fields. Herein, we demonstrate the cold-welding mechanism of nanoporous metals with various combinations using molecular dynamics simulations. This study shows that it is possible to cold-weld two nanoporous metals to form a novel composite material. The influence of temperature, in the range of 300-900 K, on the mechanical properties of the resultant composite material was investigated. With an increase in temperature, the weld stress and the mechanical strength of the nanoporous structures significantly decreased as an increase in disorder magnitude was observed. These results could lead to bottom-up nanofabrication and nanoassembly of combined nanoporous metals for high mechanical performance.