Ni4Ti3 Precipitation during Ageing of MARES NiTi Shape Memory Alloys Studied by FEG-SEM

TRANSFORMATION BEHAVIOR OF NiTi SHAPE MEMORY ALLOYS TREATED BY THERMOMECHANICAL PROCESSING USING DSC

Abstract: In the present study the effect of thermomechanical treatment (cold work and annealing) on the transformation behavior of NiTi shape memory alloys was studied. Differential scanning calorimetry was used to determine transformation temperature and its relation to precipitates and defects. Three alloys including Ti-50.3at.% Ni, Ti-50.5at.% Ni (reclamated orthodontic wires) and 50.6at...

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...

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...

NiTi Shape Memory Alloys, Promising Materials in Orthopedic Applications