Phase-transforming Ag-NiTi 3-D interpenetrating-phase composite with high recoverable strain, strength and electrical conductivity

It is of particular interest to achieve high elastic recoverable strain in the electrical contact materials while maintaining good electrical conductivity and decent tensile strength. It remains a challenge, especially for bulk-sized metallic materials, as the electrical conductivity and elastic strain limit (or tensile strength) are often mutually exclusive. Here, we present a material design strategy for overcoming this conflict by developing a Ag-NiTi composite with an interpenetrating-phase architecture via infiltrating Ag melt into the partially sintered porous NiTi scaffold. The composite exhibits a good combination of properties with high electrical conductivity comparable to metals, large elastic recoverable strain superior to most of bulk-sized conductive metals as well as higher tensile strength than most of alloys/composites based on silver and other noble metals. This new finding demonstrates that the interpenetrating-phase architecture design is promising for developing new materials for electrical contact application.