A constitutive model considering secondary phase harden and size effect in plastic deformation of Cu-3 wt%Ag-0.5 wt%Zr thin sheet

The effect of grain size and the ratio of specimen thickness to grain size on the deformation behaviors of Cu-3 wt%Ag-0.5 wt%Zr thin sheet is investigated by tensile test. For investigating the role of precipitates being generated by age process on the size effect of the thin samples, a constitutive equation is constructed by considering secondary phase hardening behavior and surface layer model. The results suggest that the critical feature value (grain size/thickness) of size effect is equal to 0.2-0.25 which is very similar to that of pure copper. However, because the precipitates strengthen role will weakness in the surface of specimen when there are only 4-5 grains across the specimen thickness, the size effect is presented more evident.