Investigation of Ni-and Ti-content influence on microstructure and phase transformation behavior of NiTi SMA alloyed with Ag

Abstract

NiTi Shape Memory Alloys (SMA) became an interesting research field in metallurgy and physics, among many others, since its advent, back in 1960's. Up to date, this interest remains due to the great range of unexploited research possibilities, in addition to the large number of application accessed by these alloys. Within those research possibilities, NiTi SMA has been used as the basis for new alloys by the introduction of a third, and even a forty, chemical element, what is called NiTi-based SMA. Silver addition was made via arc remelting to produce Ni54.99Ti43,01Ag2,00 and Ni52,99Ti45,01Ag2,00 wt.%, so that silver acts as a substitute for Ni in Ti-rich, as well as a substitute for Ti in Nirich alloys, respectively; for comparison reasons, an alloy Ni53,99Ti44,01Ag2,00, with near-equiatomic Ni:Ti relationship, was melted. Remarks on metallurgy of ingot melting, microstructure developed and thermal properties of these alloys was accessed.