Precipitation hardening of Cu-Fe-Cr alloys - Part II - Microstructural characterisation

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. Promising properties have been measured for the following all oys: Cu-0.7wt%Cr-0.3wt%Fe and Cu-0.7wt%Cr-2.0wt%Fe. This paper reports on t he microstructural characterisation of these alloys and discusses the mecha nical and electrical properties of these alloys in terms of their microstru cture, particularly the formation of precipitates. These alloys have evince d properties that warrant further investigation. Cost modelling has shown t hat Cu-0.7wt%Cr-0.3wt%Fe is approximately 25% cheaper to produce than comme rcial Cu-1%Cr. It has also been shown to be more cost efficient on a yield stress and % IACS per dollar basis. The reason for the cost saving is that the Cu-0.7%Cr-0.3%Fe alloy can be made with low carbon ferro-chrome additio ns as the source of chromium rather than the more expensive Cu-Cr master-al loy. For applications in which cost is one of the primary materials selecti on criteria, it is envisaged that there would be numerous applications in b oth cast and wrought form, where the Cu-0.7%Cr-0.3%Fe alloy would be more s uitable than Cu-1%Cr. (C) 2001 Kluwer Academic Publishers.