Atomistic insights into cold welding process of high-entropy alloy nanowires

This research applied molecular dynamics (MD) simulations to investigate the influences of contact pressure, temperature, crystal orientation, and chemical composition on the characteristics of the cold welding joints of CoNiCrFeMn high-entropy alloy (HEA) nanowires. The findings indicate that defect-free cold welded joints can be successfully formed within a contact pressure range of 10 to 10,000 Pa. In addition, changing the contact orientation could cause a significant change in the structure transformation level. The dislocation distribution is continuous when the top and lower blocks are oriented in the same direction. Dislocation lines, on the other hand, stop at the interfacial area and have a discontinuous shape when the weld joints are formed from different orientations. Furthermore, creating from the same orientations leads to a higher ultimate tensile strength (UTS) value than the different orientation cases. In the temperature range of 150 K-350 K, the deformation behaviors of the cold weld joint are stable. Besides, there was no noticeable change in the weld joint when the composition changed. Because of the strong crystal structure of the cold welding joints, the UTS values of the cold-welded joints range from 13.2 to 17.4 GPa, comparable to the bulk samples.