The uniaxial thermomechanical behavior of a polycrystalline Fe-9%Cr-5%Ni-14%Mn-6%Si (all wt.%) shape memory alloy is investigated for both tensile and compressive stress states. The martensite start stresses measured upon tension and compression loading of austenite depend linearly on temperature, thus forming straight lines in the stress-temperature regime. The lines belonging to tension and c...

Austenite formation and its decomposition control the final microstructure and performance of steel welds. This paper presents an in-situ characterization of austenite formation and its decomposition in both the fusion zone (FZ) and heat-affected zone (HAZ) of an Fe-C-Al-Mn steel using time-resolved X-ray diffraction (TRXRD) with synchrotron radiation. Measurement of X-ray diffraction spectra a...

Deformation and work hardening behavior of Fe-17Mn-0.02C steel containing ε-martensite within the austenite matrix have been investigated by means of in situ microstructural observations and x-ray diffraction analysis. During deformation, the steel shows the deformation-induced transformation of austenite → ε-martensite → α'-martensite as well as the direct transformation of austenite → α'-mart...

The goal of this paper is to analyse the effect of adding Al on the non-steady pearlite growth occurring in a Fe-C-Mn system. The results are discussed in terms of the partitioning of elements across the austenite/ferrite and austenite/cementite interfaces, and the modification of the pearlite driving force related to the change in carbon activity in austenite.

Two kinds of austenite grow from d-ferrite during the cooling of the duplex stainless steel weld deposits studied here, Widmanstätten plates and allotriomorphs which precipitate at d–d grain boundaries. It is found using microtexture measurements that the preferred crystallographic orientation of the Widmanstätten austenite can be estimated using established theory if it is assumed that there i...

Nano/submicron austenitic stainless steels have attracted increasing attention over the past few years due to fine structural control for tailoring engineering properties. At the nano/submicron grain scales, grain boundary strengthening can be significant, while ductility remains attractive. To achieve a nano/ submicron grain size, metastable austenitic stainless steels are heavily cold-worked,...

Besides permitting an accurate determination of the ferromagnetic-to-paramagnetic phase transition temperature and the characteristic temperatures for the beginning and end of the growth of martensite (austenite) phase at the expense of austenite (martensite) phase while cooling (heating), the results of an extensive ac susceptibility, sound velocity and internal friction investigation of the t...

The tempering of two–phase mixtures of bainitic ferrite and carbon–enriched retained austenite has been investigated in an effort to separate the reactions that occur at elevated temperatures from any transformation during cooling to ambient conditions. It is demonstrated using synchrotron X–radiation measurements, that the residue of austenite left at the tempering temperature partly decompose...

Many aspects of the crystallographic texture which develops when austenite transforms into martensite or bainite are well established because the process by which the parent lattice is transformed into that of the product is mathematically defined. This is not the case when the ferrite forms by a reconstructive mechanism. The allotriomorphic ferrite nucleates heterogeneously at austenite grain ...

A bainitic microstructure with fine ferrite plates (20 to 40 nm) in a matrix of high-carbon retained austenite, obtained by isothermal transformation at 200°C, was characterized with an energy-compensated optical position-sensitive three-dimensional atom probe. The average carbon concentration in the austenite was found to be 8.0±1.6 at.% and in the bainitic ferrite 1.1±0.7 at.%. The latter con...