Recent experimental research indicates that superelastic shape memory alloy nickel–titanium (NiTi) is superior to stainless steel against wear and could be applied in tribological engineering. It is believed that the super wear resistance of shape memory alloys is mainly due to the recovery of the superelastic deformation. Our recent wear study indicates that wear rate is very sensitive to the ...

The aim of this paper is to analyse the generation of internal stresses during the predeformation of NiTi shape memory alloys in the martensitic state. This allows to determine the initial stress state in which the material will transform during the shape memory effect due to heating coilsecutively to this prestrain. In that way a three-dimensional finite element model of the deformation of sha...

T his is the third paper in our series to identify unusual phenomena and to provide recommendations for the thermo-mechanical characterization of shape memory alloy (SMA) wire. Part 1 provided some basic background of the martensitic transformations responsible for the shape memory effect and superelasticity1. The characterization of two typical NiTi SMA alloys began with differential scanning ...

The performance characteristics of shape memory alloys operating in an overtemperature shut-off valve at a temperature of 95OC for up to 2000 hours are presented. Alloys of NiTi, Cu-Al-Ni and Cu-Zn-Al have been characterised under these ageing conditions. The effect of altering the processing parameters, viz solution treatment temperature, quenching technique and training procedure were examine...

Shape memory alloys (SMAs) impart a potential application in a wide range in microand nano-industrial world. Classic properties such as free recovery or pseudo-elasticity still needed further specifications in smart materials or micro-actuators applications. Nowadays, a primary goal is achieved that these materials offer a price-competitive advantage compared to other functional materials desig...

For Micro-electro-mechanical System (MEMS) applications, TiNi-based thin film Shape Memory Alloys (SMAs) possess many desirable properties, such as high power density, large transformation stress and strain upon heating and cooling, superelasticity and biocompatibility. In this paper, recent development in TiNi-based thin film SMA and microactuator Thin film SMAs and microactuators 209 applicat...

Material scientists predict a prominent role in the future for self-repairing and intelligent materials. Throughout the last few years, this concept has found growing interest as a result of the rise of a new class of polymers. These so-called shape-memory polymers by far surpass well-known metallic shape-memory alloys in their shape-memory properties. As a consequence of the relatively easy ma...

Although medical applications for shape memory alloys (SMA) now dominate in today’s market, there are many applications in the industrial sector which have reached large volume production that far surpass the material usage in the medical fields. In the early growth of shape memory alloy technology the most important applications were for fasteners and couplings, mainly in the military sector. ...

In this study, in order to obtain a functionally graded material, NiTi strips were annealed at 350°C, 450°C and 550°C in a furnace using an assembly that allowed a temperature gradient along them, and their transformation temperatures were studied by Differential Scanning Calorimetry (DSC). Furthermore, the strips were bent at both ends and dipped into a water bath at room temperature which was...

Single crystalline and polycrystalline CoxNiyGa100-(x+y), 41<xCo<62 and 19.3<xNi<32.7 [at%], Ferromagnetic Shape Memory Alloys (FMSMAs) have been produced in the range of the Heusler-type composition. Elasto-mechanical properties have been analyzed for the annealed and quenched states, respectively. The mechanical spectroscopy data show the occurrence of martensitic phase transformations with t...