Effects of work-hardening and post thermal-treatment on tensile behaviour of solder-affected copper

Abstract

In order to explore the reuse potential of waste/scraped copper, an effective characterization of its functional properties under various operating conditions is of great practical importance. The present paper is an attempt to reconnoiter the solder-affected waste copper for high-value engineering applications through the characterization of major mechanical properties. More specifically, the tensile properties of traditional lead-solder-affected copper are investigated and analyzed under the influence of work-hardening and post-thermal treatments. The influential effects of individual elements of the solder on the tensile properties of copper are discussed in a comparative fashion, in which two additional alloy samples, namely, high-copper/tin alloy and high-copper/lead alloy are taken into consideration together with those of copper–tin–lead–alloy as well as pure copper samples. The results of the investigation show that the inclusion of trace-amount of tin and lead in copper affects the corresponding tensile behaviour quite significantly. The strength rising trends due to cold working are observed to be more prominent for the inclusion of lead compared to that of tin. The post-thermal treatments of the work-hardened alloy samples have lowered ultimate strength, yield strength and elastic modulus, but increased the fracture elongation at elevated temperatures. Strain rate variations are also found to be highly influential on all the tensile properties of the solder-affected alloys. Micrographs of the alloy samples have verified the changes in grain shape and grain size responsible for the variation of tensile properties.