Performance of a copper-silver alloy as an electromagnetic launcher conductor material

In a previous paper, a copper-silver conductor with a strength/conductivity combination of 600 MPa and 85% IACS was manufactured and characterized. The strength and conductivity combination in the as-cast copper-16% mass percent silver composition made copper-silver alloys attractive materials for consideration as electromagnetic launcher conductors. In this paper, the alloy copper-24% mass percent silver (Cu-24%Ag) is evaluated experimentally by coupon testing in a launcher. Material microstructure change is evaluated by optical stereoscope, optical microscope and scanning electron microscope. Other material properties studied include hardness as well as thermal and electrical conductivity. The changes in material properties are related to the initial state of strain in the test specimen. The results are explained in terms of the relative contributions of strain hardening and substitutional solid-solution strengthening to the overall strength of the conducting copper-silver. Local compressive forces produced plastic flow in softer specimens. Subtle changes in microstructure were observed, and new structures with equivalent properties were observed to develop.