Recent development of advanced precipitation-strengthened Cu alloys with high strength and conductivity: A review

Precipitation-strengthened Cu alloys with high strength and conductivity (HSC) has become widespread in the electronic and electrical industries. Although pure Cu exhibits high electrical and thermal conductivity, its strength is insufficient. Thus, the primary objective of developing Cu alloys with HSC is to substantially enhance their strength while retaining high electrical conductivity (EC). This review provides an overview of the research progress on typical precipitation-strengthened Cu-Ni-Si, Cu-Ti and Cu-Cr-Zr alloys, as well as the strengthening mechanisms employed. In particular, we discuss hetero-deformation induced (HDI) hardening, the construction and effect of heterogenous structure in Cu alloys, and how the trade-off between strength, ductility, and EC can be better addressed by constructing a coupling distribution of hard and soft domains in alloys. Moreover, based on the precipitation strengthening mechanism, we calculate the Orowan contribution of two uniform ideal distributions of disc-like shape δ-Ni2Si phases, and propose an outlook. Notably, controlling the growth of phases to achieve maximum strength contribution is a key research breakthrough. Additionally, the development of Cu alloys with HSC must consider large-scale industrialization and production costs.