In situ neutron diffraction experiment was used during tensile testing at room temperature to examine the changes on the percentage and texture of both ferrite and austenite in a nanocrystalline bainitic steels transformed at two different temperatures 200°C and 300oC for different times to achieve the same phase percentages. Both samples showed an inadequate capability of austenite to transfor...

A phenomenological macroscopic plasticity model is developed for steels that exhibit strain-induced austenite-to-martensite transformation. The model makes use of a stress-state dependent transformation kinetics law that accounts for both the effects of the stress triaxiality and the Lode angle on the rate of transformation. The macroscopic strain hardening is due to nonlinear kinematic hardeni...

Neutron diffraction spectra were obtained during various stages of a reversible stress-induced austenite to martensite phase transformation in superelastic NiTi. This was accomplished by neutron diffraction measurements on bulk polycrystalline NiTi samples simultaneously subjected to mechanical loading. Analysis of the data was carried out using individual lattice plane ~hkl! reflections as wel...

SUS440 is a high-carbon stainless steel, and its martensite matrix has high heat resistance, high corrosion resistance, and high pressure resistance. It has been widely used in mechanical parts and critical materials. However, the SUS440 martempered matrix has reliability problems in thin plate applications and thus research uses different austempering heat treatments (tempering temperature: 20...

The features of martensite transformation in Fe (31 32)% Ni melt-quenched alloys are considered. The meltquenching was realized by spinning technique with variable parameters. The influence of the melt-quenching on structural and kinetics transformation parameters is revealed. In particular Ms point is shown to decrease but volume percentage of athermal martensite is found to be invariable with...

The medium Mn steels are gaining increasing attention due to their excellent combination of mechanical properties and material cost. A cold-rolled 0.1C5Mn medium Mn steel with a ferrite matrix plus metastable austenite duplex microstructure was resistance spot-welded with various welding currents and times. The nugget size rose with the increase of heat input, but when the welding current excee...