The characterization of cold welding process in CuZr metallic glasses with dissimilar alloying compositions

This work aimed to investigate the cold welding process of dissimilar Cu₆₀Zr₄₀/Cu₅₀Zr₅₀ metallic glass (MG) system through the molecular dynamics (MD) simulation. The mechanical properties and plasticity behavior of the joint zone were also studied with the consideration of stress variations and shear atomic strains under the nanoindentation. The results indicated that the joining evolution was accompanied by the accumulation of shear events in the joint zone. However, one side of the joint was more affected by the atomic rearrangements, which were due to the dissimilar mechanical features of Cu₆₀Zr₄₀ and Cu₅₀Zr₅₀ alloys. The nanoindentation results also showed that the joint zone was considerably softer than the base alloys; however, no sudden shear propagation appeared in this part of the assembly. The strain maps of shear atomic strain under the nanoindentation indicated that the atomic rearrangement and shear band interactions were unsymmetrical in the joint zone so that the Cu₅₀Zr₅₀ side tended to form finer shear bands with more interactive features. Finally, it was concluded that a sound metallurgical bond was attained in the Cu₆₀Zr₄₀/Cu₅₀Zr₅₀ system; however, the good plasticity may come at the expense of strength in the joint zone.