The Effect Of Copper Addition In The Transformation Temperatures In Rapid Solidified Ti–Ni-Cu Alloys

George Carlos S Anselmo, Walman Benicio de Castro, Carlos José de Araújo

University Federal de Campina Grande, UFCG, Campina Grande-PB, Brazil

Ternary rapidly solidified NiTi alloys were produced and tested in this research work. Cu was added to a near-equiatomic Ti₅₀Ni₅₀ alloy, by substituting Ni. Three compositions were studied: Ti50Ni50-xCux(x= 4, 5, 6). Samples with the ribbons shape were obtained, in order to test the effects of different rapid solidification rates. The aim of this research was to analyze the use of rapid solidification (Melt Spinning), with speed of the copper round (38 m/s and 50 m/s). It was found that as Cu content increased, the transformation temperatures rapidly decrease and they reach its minima between 4 and 6 at.% of Cu. Moreover, the Cu addition reduces the transformation hysteresis. Some precipitates were found in the ternary alloys and Ni and Cu showed a linear exchanging tendency in the precipitates, in the explored range of Cu content.

Keywords: Rapid Solidification, Temperature of Martensitic Transformation, Shape Memory Alloy.