The growth and propagation behavior of austenite-to-bainite isothermal transformation in laser-cladded, Si-rich, and Fe-based coatings is investigated. The crystallographic features, orientation relationship at different isothermal temperatures, and the morphology of the nanostructured bainite are determined. The Nishiyama-Wassermann type orientation relationship is observed at a high temperatu...

A theory is developed for the evolution of bainite as a function of time, temperature, chemical composition and austenite grain size. The model takes into account the details of the mechanism of transformation, including the fact that nucleation begins at the austenite grain surfaces, and that the growth of a sheaf occurs by the repeated nucleation of small platelets. Predictions made using the...

The mechanical behaviour of Fe-C aiioys have been determined in their phase transformation ranges during isothermal or anisothermal transformations. Two models an analytical model and a fii te element model have been used in order to calculate the behaviour of the material. Considering a macroscopic scale, these models show that the mechanical behaviour can be well described when an additional ...

Recently, the grain boundary−intragranular nucleation of ferrite has received great attention seeking for the improvement of the toughness in the steel, specially when conventional austenite grain refinement techniques are not enough. This paper deals with some relevant aspects about the competitive process of allotriomorphic and idiomorphic ferrite transformations in a medium carbon vanadium-t...

The hot stamping of tailored properties is widely established in the automotive industry. However, unlike conventional press hardening, this technique designed to generate varying mechanical by controlling cooling rate locally. Current material models cannot accurately represent locally very different thermomechanical paths. This research aims address problem developing a new phase transformati...

This paper presents a geometric method for parameterization, matching, and analysis of surface shapes. Surfaces are parameterized and represented by intrinsic coordinate maps derived from the conformal structure of the shape. This parameterization is invariant to rigid transformations of the shape, as well as angle-preserving parameterizations of the surface. Shape matching between coordinate m...

A method for extracting the parameters describing the process of grain growth from calorimetric data is presented. Both isothermal and scanning experiments are considered. It is demonstrated that the Kissinger method used for determining the activation enthalpy of a nucleation-and-growth process can be used for a grain growth process as well. Characteristic differences between the signals, both...

The numerical simulation of all steps of the production of a steel workpiece is nowadays a widely used tool for understanding and optimization of such processes. The transformation of austenite into ferritic phases is an important feature of heat treatment of steel. Good models for the non-isothermal phase transition are a necessary prerequisite for various other modeling steps. We evaluate som...