SHS as possible alternative production route for Ni50-xTi50Cux SMA: advantages and limitations

Shape memory alloys are extremely interesting smart materials, that can be employed in several applications, from biomedical to automotive field. Their use is limited primarily because of their costs related not only to alloy production but also to processability. Recently, costs reduced due to increased number of producerrs, and new production technologies are tryed in order to achieve nearly net shape products. Among these processes SHS could be considered. NiTi can be produced by SHS even if limitations are encountered due to secondary phases formation, but limited studies are available about processability of ternary alloys through SHS. In this study the characteristics of NiTiCu shape memory alloys produced by SHS are presented. Microstructural investigation revealed the presence of NiTiCu matrix phase, characterised by shape memory properties, together with secondary phases which do not present any transformation. Calorimetric analyses were performed in order to assess transformation temperatures. XRD investigation performed at room temperature, above and below transformation temperatures helped in the identification of the type of phase transformation. Results were compared with typical properties of conventionally produced NiTiCu alloys, and possible applications are also discussed.