Ambient-Temperature Indentation Creep of Shape Memory NiTi Alloys: Additively Manufactured versus Cast

Spherical Indentation Hardness of Shape Memory Alloys

Functionally graded NiTi shape memory alloys

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...

Shape Memory Effect in Cast Versus Deformation-Processed NiTiNb Alloys

The shape memory effect (SME) response of a deformation-processed NiTiNb shape memory alloy is benchmarked against the response of a cast alloy. The insoluble Nb element ternary addition is known to widen the hysteresis with respect to the binary NiTi alloy. Cast microstructures naturally consist of a cellular arrangement of characteristic eutectic microconstituents surrounding primary matrix r...

Characterization of smart MARFOS NiTi shape memory alloys

In the present study, structural characterization of NiTi smart shape memory alloys (SMAs), produced by an alternative powder metallurgy approach named mechanically activated reactive forging (MARFOS), was carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was observed that MARFOS materials had a multiphase nanocrys...

Atomistic study of nanotwins in NiTi shape memory alloys

Atomistic simulations are performed to study the structure and geometrical limit of nanoscale twins in NiTi shape memory alloys. We analyze compound twins as narrow as 1 nm, involving a few atomic layers. A novel nanotwinned structure is found, forming through the martensitic transformation of sublattices. We predict the temperatures of phase transformation, which are consistent with experiment...