the dynamic behavior of three high manganese steels with very different stacking faultenergy (sfe) values (4-30 mj/m2) were studied using high strain rate torsional tests. the hotrolledmicrostructure of the steel with the lowest sfe of 4 mj/m2 consisted of a duplex mixture ofaustenite and ε-martensite, but those of the other two steels were fully austenitic. the deformedmicrostructures were stu...

An extra low carbon martensitic stainless steel with 16% ultrafine grained metastable reverted austenite was subjected to uniaxial tensile testing and investigated in-situ energy-dispersive synchrotron X-ray diffraction (XRD) electron backscatter (EBSD) reveal the complex interplay between stress, strain transformation. In-situ XRD demonstrated that, upon surpassing yield strength, fraction of ...

In metastable austenitic stainless steels, strain-induced martensitic transformation during plastic deformation enhances work hardening of the material, increasing its strength and in some cases also ductility.1,2) The presence of α’-martensite, however, may increase the susceptibility of these materials to hydrogen embrittlement phenomena, for example delayed cracking.3–6) Delayed cracking can...

This study was conducted in order to investigate the influence of plastic deformation on the transformation of retained austenite in a TRIP steel with a high content of Al and a low content of Si. To the aim, appropriate treatments were used to produce the starting material (TRIP steel). The microstructure of the obtained steel was composed of bainite and phases including ferrite and retained a...

Magnetic shape memory properties of Ni-Mn-Ga single crystals were characterized by measurement of stress-induced martensite reorientation under constant magnetic fields. Also magnetic field-induced strain as a function of the applied magnetic field under different constant compressive stress levels has been investigated. All the experiments were performed at room temperature in which the sample...

The formation of stress-induced α′′ martensite in a metastable β Ti-Mo-based alloy has been studied using X-ray diffraction and transmission electron microscopy. The martensite nucleates heterogeneously at pre-existing sub-grain boundaries by dissociation of the boundary dislocations which bow out on inclined planes. The growth of martensite laths from the resultant stacking faults occurs by th...

This work is to the best of my knowledge original, except where acknowledgements and references are made to previous work. Neither this, nor any substantially similar dissertation has been or is being submitted for any other degree, diploma or other qualification at any other university. This dissertation does not exceed 60,000 words in length. Abstract iii DFT Pak, Jun Hak 20080959 Coalesced s...

Modern TRIP assisted steels contain retained austenite with carbon concentrations in excess of 1 wt-%. Some of their mechanical properties, in particular the toughness and ductility, rely on the diffusionless transformation of this austenite into high-carbon martensite, induced by stress and strain. The properties can be excellent in spite of the fact that freshly formed high-carbon martensite ...

The fct martensite morphology and the martensite transformation temperatures are examined for Pd-rich Fe–Pd–Pt alloys, which have the composition of Fe–(xPdyPt)xþy1⁄430 at:%. The replacement of Pd with Pt content causes solution hardening. The shape memory effects are investigated below the Af temperatures. Above the Af temperatures, the stress induced martensite in several grains completely di...