Microstructure and mechanical properties of Sn–Cu alloys for detonating and explosive cords

Abstract

ABSTRACTTo develop alloys as the substitute of Pb-based alloys for cladding materials in detonating and explosive cords, the materials requirement was analysed and Sn–Cu based alloys were selected as potential candidates. Four alloys including Sn–0.3 wt-%Cu, Sn–0.5 wt-%Cu, Sn–0.7 wt-%Cu, and Sn–1.0 wt-%Cu were prepared by casting and rolling. Microstructures of as-cast Sn–Cu alloys comprised Sn solutions with Cu6Sn5 intermetallic in the matrix. The as-rolled hypoeutectic Sn–Cu alloys (0.3–0.5 wt-%Cu) offered the yield strength from 26.1 to 31.9 MPa, UTS from 30.1 to 34 MPa and elongation from 86.4 to 87.5%, which were found to be appropriate for detonating and explosive cords. Particularly, the Sn–Cu alloys exhibited strain softening behaviour under tensile stress, which will benefit cladding manufacture and subsequent processing after assembly with high-energy explosive materials.