Since the end of the nineteenth century, automated root canal instrumentation has been available, but systems had many problems. The challenges of increased canal blockage, instrument breakage, and insufficient canal debridement were related to the use of stainless steel instruments and have been dramatically improved with the introduction of nickel-titanium (NiTi) files. The first useable NiTi...

NiTi is the most used shape-memory alloy; nonetheless, a lack of understanding remains regarding the associated structures and transitions, including their barriers. Using a generalized solid-state nudged elastic band method implemented via density-functional theory, we detail the structural transformations in NiTi relevant to shape memory: those between a body-centered orthorhombic (bco) groun...

This work focuses on application of the laser forming process to NiTi shape memory alloys. While all NiTi shape memory alloys exhibit both superelasticity and the shape memory effect, this study is restricted to a temperature range over which only the superelastic effect will be active. Specifically, this work addresses laser forming induced macroscopic bending deformations, postprocess residua...

This paper presents a comparative theoretical study of the performance of a set of controllers for improving the speed of actuators based on shape memory alloys (SMAs), especially on Nitinol (NiTi). To prevent overheating and thermal fatigue, these controllers take into account the maximum heating current at which a NiTi element can safely be heated. The thermal behaviour of NiTi is first model...

The transformation behaviour of AA2124 alloys reinforced NiTi particulates of 10 vol pct and 20 vol pct has been studied by differential scanning calorimetry (DSC), thermoelectric power (TEP) and internal friction (IF). Addition of NiTi particulates increase the damping capacity as well as the precipitation kinetics of AA2124 composites with respect to the base AA2124. Heat treatments performed...

Ni(3+) doped NiTi layered double hydroxide (NiTi-LDH) monolayer nanosheets with a particle size of ∼ 20 nm and a thickness of ∼ 0.9 nm have been successfully prepared through a facile bottom-up approach. These NiTi-LDH monolayer nanosheets exhibit excellent supercapacitor performance, including a high specific pseudocapacitance (2310 F g(-1) at 1.5 A g(-1)) and long durability compared with bul...

The compressive creep behavior of nickel-rich B2–NiTi (with 50–140 lm grain size) was studied over the stress range 3–11 MPa and the temperature range 950–1100 C. The stress exponent (n = 2.7) and activation energy (Q = 155 kJ mol ) are compared with a literature review of NiTi creep studies performed over lower temperature and/or higher stresses. Possible explanations for discrepancies between...

We present results from a systematic study linking material microstructure to monotonic and fatigue properties of NiTi shape memory alloys. We consider Ni-rich materials that are either (1) hot rolled or (2) hot rolled and cold drawn. In addition to the two material processing routes, heat treatments are used to systematically alter material microstructure giving rise to a broad range of therma...

Superelastic NiTi and NiTi-TiC composites were subjected to static uniaxial compressive loading while neutron diffraction spectra were simultaneously acquired. A methodology was established to obtain quantitative strain, texture and phase volume fraction information during the forward and reverse stress-induced martensitic transformation. Despite the presence of 10 vol. % of stiff TiC particles...