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 ...

In the present study, isothermal decomposition of austenite to bainite in 1.0 wt% carbon, 0.21% silicon steel during partitioning step a quenching and (Q&P) heat treatment has been investigated dilatometer temperature range 200 350 °C compared conventional austempering treatment. The transformation was shortened by about 75% presence pre-existing martensite (QP). kinetics is described well-...

We have performed molecular dynamics simulations of Fe 80 Ni 20 alloys using an inter-atomic potential of the EAM-type which allows the simulation of the martensite-austenite transition. We present results, showing the development of an inhomogeneous shear system on a nanoscale during the thermally induced austenitic transformation. In addition to this we obtained the phonon dispersion relation...

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...

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...

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available online at http://meteoritics.org 553 © The Meteoritical Society, 2006. Printed in USA. The formation of plessite in meteoritic metal J. I. GOLDSTEIN1* and J. R. MICHAEL2 1Department of Mechanical and Industrial Engineering, 313 Engineering Lab, University of Massachusetts, 160 Governors Drive, Amherst, Massachusetts 01003, USA 2Materials Characterization Department, Sandia National La...

structural steels with very high strength levels are often referred to as ultrahigh-strength steels (uhss). the usage of uhss has been extensively studied in aerospace industries and offshore platforms. in this study, medium carbon low alloy steel (ams6305) was thermomechanicaly treated to obtain an ultra-high strength bainitic steel for aircraft engine compressor disk. a novel themomechanical ...

Superelastic NiTi (51.0 at.% Ni) specimens reinforced with 0, 10 and 20 vol.% TiC particles were deformed under uniaxial compression while neutron diffraction spectra were collected. The experiments yielded in-situ measurements of the thermoelastic stress-induced transformation. The evolution of austenite/martensite phase fractions and of elastic strains in the reinforcing TiC particles and the...