Precipitation hardening of Cu-Fe-Cr alloys - Part I - Mechanical and electrical properties

This research is part of a project whose scope was to investigate the engin eering properties of new non-commercial alloy formulations based on the Cu rich corner of the Cu-Fe-Cr ternary system with the primary aim of explorin g the development of a new cost-effective high-strength, high-conductivity copper alloy. The literature indicated that Cu rich Cu-Cr and Cu-Fe alloys have been thoroughly investigated. A number of commercial alloys have been developed and these are used for a variety of applications requiring combin ations of high-strength, high-conductivity and resistance to softening. Lit tle evidence was found in the literature that the Cu rich corner of the Cu- Fe-Cr system had previously been investigated for the purpose of developing high-strength, high-conductivity copper alloys resistant to softening. The aim of these present investigations was to explore the possibility that ne w alloys could be developed that combined the properties of both sets of al loys, ie large precipitation hardening response combined with the ability t o stabilise cold worked microstructures to high temperatures while at the s ame maintain high electrical conductivity. To assess the feasibility of thi s goal the following alloys were chosen for investigation: Cu-0.7wt%Cr-0.3w t%Fe, Cu-0.7wt%Cr-0.8wt%Fe, Cu-0.7wt%Cr-2.0wt%Fe. This paper reports on the mechanical property investigation which indicated that the Cu-0.7wt%Cr-0.3 wt%Fe, and Cu-0.7wt%Cr-2.0wt%Fe alloys were worthy of further investigation . (C) 2001 Kluwer Academic Publishers.