Cold-rolling influence on microstructure and mechanical properties of NiCr - Ag composites and porous NiCr obtained by liquid metal dealloying

Abstract

To obtain anisotropic nanoporous NiCr, some NiCr-Ag composites were prepared using a liquid metal dealloying method and were cold rolled before etching. While immersing (Ni90Cr10)60Cu40 precursors in a molten Ag bath, Cu atoms selectively migrate into the Ag bath. After cooling down to room temperature, the resulting microstructure is a bi-continuous structure of NiCr and Ag (with Cu in solid solution). These ingots are strong enough to be cold rolled in one or two (perpendicular) directions with a thickness reduction of 70%. A final etching step removes the Ag solid-state solution phase. The influence of cold rolling on the microstructure was investigated using X-ray tomography and on the mechanical properties using nanoindentation. We will show how introducing anisotropy into the microstructure and in the mechanical properties was successful while being able to preserve the porous state.