Microstructural characteristics of a nanoeutectic Ag-Cu alloy processed by surface mechanical attrition treatment

A nanostructured eutectic Ag-Cu alloy with alternate Ag and Cu lamellae was processed by surface mechanical attrition treatment (SMAT). The orientation/phase distributions of the eutectic Ag-Cu before and after SMAT were investigated using transmission electron microscopy combined with automated crystal orientation mapping. After SMAT, the top surface layer was transformed into a composite with isolated Cu phase dispersed in Ag. The interphase boundaries in the top surface layer were changed from the original cube-on-cube and hetero-twin orientation relationships into general large-angle boundaries accordingly.