INTRODUCTION To improve the fracture resistance of nickel-titanium (NiTi) files, manufacturers have introduced new alloys and developed new manufacturing processes for the fabrication of NiTi files. This study aimed to examine the phase transformation behavior and microstructure of NiTi instruments from a novel controlled memory NiTi wire (CM wire). METHODS Instruments of EndoSequence (ES), P...

There are two well-known phenomena associated with the bainite reaction, both of which have been exploited here to enhance the mechanical behaviour of steel. Firstly, the bainite plate size decreases as the transformation temperature is reduced. Secondly, it is bad to have large regions of untransformed austenite in the microstructure; this is because they can transform, under the influence of ...

The effects of increasing nickel from 3 to 7 and 9 wt. % were investigated in high strength steel weld metals with 2 wt. % manganese. It was found that nickel additions were positive for strength but negative for impact toughness. Significant segregation of nickel and manganese to interdendritic regions was observed with the two higher nickel contents. In these weld metals a mainly martensitic ...

The different techniques available for the accurate measurement of lattice fringe spacings are discussed and their relative merit under different circumstances assessed. The relationship between the lattice fringe spacing and the lattice parameter is further examined for both uniform and chemically inhomogeneous material. The techniques described were also applied to an investigation of carbon ...

Duplex stainless steel multi-pass welds were made at 0.15 MPa, 0.45 MPa, and 0.75 MPa pressure, simulating underwater dry hyperbaric welding by the flux-cored arc welding (FCAW) method, with welds of normal pressure as a benchmark. The purpose of this work was to estimate the effect of ambient pressure on the microstructure, pitting corrosion resistance and impact toughness of the weld metal. T...

We perform density-functional theory ~DFT! calculations of carbon dissolution and diffusion in iron, the latter being a typical example of interstitial diffusion. The Kohn-Sham equations are solved with periodic boundary conditions and within the projector-augmented-wave formalism, using the generalized gradient approximation for electron exchange and correlation. With the solution enthalpy as ...

In this paper we present a walking pattern filter for Shape Memory Alloy (SMA) actuated biped robots. SMAs are known for their slow response. The actuation speed limitation can potentially lead to stability problems for biped robots. This filter adapts the human motion for a SMA biped in order to have a stable walking pattern. The Zero Moment Point (ZMP) is used as a main criterion of the filte...

A medium Mn steel has been designed to achieve an excellent combination of strength and ductility based on the TRIP (Transformation Induced Plasticity) concept for automotive applications. Following six passes of hot rolling at 850 °C, the Fe-7.9Mn-0.14Si-0.05Al-0.07C (wt.%) steel was warm-rolled at 630 °C for seven passes and subsequently air cooled to room temperature. The sample was subseque...