Retained austenite (RA) transformation and its role in the mechanical properties of three low-carbon micro-alloyed quenching partitioning (Q&P) steels was investigated utilizing situ tensile tests electron microscopy. Meanwhile, RA’s strain-induced martensite (SIMT) analyzed discussed terms strengthening mechanism. The results show that ductility Q&P relies on size morphology RA. In add...

In-situ neutron diffraction measurements were performed on Fe-33Ni-0.004C alloy (33Ni alloy) and Fe-27Ni-0.5C (27Ni-0.5C during cooling from room temperature to the cryogenic (4 K) evaluate changes in lattice constants of austenite martensite, tetragonality martensite due thermally induced martensitic transformation. As transformation progressed, both alloys deviated smaller values than those p...

Methods for the dilatometric determination of the martensite start temperature of steels are discussed, with emphasis on noise in the experimental data. The methods are tested on a new set of experiments using a specially prepared steel. Relying on the first detection of expansion due to transformation is fraught with difficulties. Instead, an offset method is proposed which should enable indep...

Based on the results that the magnitude of the stabilization of retained austenite increases with increasing the amount of martensite transformed, it has been assumed that the martensitic transformation is accompanied with an increase in internal resisting stress which subsequently results in the stabilization of retained austenite. By simplifying this internal resisting stress to be a type of ...

Positron annihilation Dopplerbroadening measurements were carried out on Cu-Al-Ni based alloys to which Ti, and Ti and Mn was added. The measurements reveal a drastic effect in the S-parameter behavior when the defects anneal out at the transition from martensite to the beta phase. When crossing the transition region several times, an increase of the S-parameter value is observed. This is inter...

The redistribution of carbon after tempering of a novel nanocrystalline bainitic steel consisting of a mixture of supersaturated ferrite and retained austenite has been analyzed by atom probe tomography. No direct evidence supporting the additional carbon enrichment of austenite beyond that initially achieved during the bainite heat treatment was obtained during subsequent tempering of this hig...

The magnetostructural coupling between the structural and the magnetic transition has a crucial role in magnetoresponsive effects in a martensitic-transition system. A combination of various magnetoresponsive effects based on this coupling may facilitate the multifunctional applications of a host material. Here we demonstrate the feasibility of obtaining a stable magnetostructural coupling over...

The microstructure obtained as the weld cools from the liquid phase to ambient temperature is called the as–deposited or primary microstructure. Its major components include allotriomorphic ferrite, Widmanstätten ferrite, and acicular ferrite (Fig. 1). There may also be some martensite, retained austenite or degenerate pearlite. These latter phases occur in very small fractions, and are known b...

A giant magnetic-field-induced strain ~MFIS! of 23100 ppm has been obtained in Heusler alloy Ni52Mn22.2Ga25.8 single crystal in the @001# direction at a temperature from 23 to 31 °C. This MFIS reaches saturation in an applied field about 6 kOe, and exhibits the same amplitude with an opposite sign while the field is perpendicular to the samples. According to a previous model, this MFIS associat...

Steels with a mixed microstructure of allotriomorphic ferrite, bainitic ferrite, retained austenite and martensite have potentially good combinations of high strength and formability. This work describes a kinetic theory for the formation of bainite in steels where the precipitation of carbides is suppressed. The theory is based on the mechanism of transformation. It includes, for example, a nu...