scholarly journals A Kinetic Model for Tribological Surface Transformations Occuring on the Railroads: Irreversible Near-Surface Metallurgical Transformations

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
G. Antoni
Keyword(s):  
Kinetic Model ◽  
Phase Transformations ◽  
Solid Phase ◽  
Manufacturing Processes ◽  
Near Surface ◽  
Railroad Network

During the manufacturing processes or the operational phases, some materials are liable to undergo metallurgical phenomena known as irreversible solid-solid phase transformations or Tribological Surface Transformations (TSTs). The treads of several rails in the French railroad network have been affected by TSTs. The kinetic model presented in this paper describes the initiation of TSTs and their development near the rail surface.

scholarly journals On a New Kinetic Modelling Approach of the Irreversible Quasi-Surface Metallurgical Phase Transformations

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Grégory Antoni
Keyword(s):  
Phase Transformations ◽  
Solid Phase ◽  
Kinetic Modelling ◽  
Behavioral Model ◽  
Internal Variables ◽  
Manufacturing Processes ◽  
Specific Response ◽  
Continuum Thermodynamics ◽  
Metallic Materials ◽  
Modelling Approach

Irreversible quasi-surface metallurgical phase transformations are the specific response of some metallic materials—such as metals and alloys—subjected to high thermomechanical loads applied very near their surface during the manufacturing processes or after being put into operation. These solid/solid phase transformations can be observed, for example, on the tread of many rails in railroad networks frequented by freight trains. The severe thermal and mechanical loads imposed on the surface of the rails and in the immediate vicinity of the surface by the wheel/rail contact often result in highly localized irreversible metallurgical transformations. A new kinetic model based on a previous study is presented here, which accounts more realistically for the nucleation and growth of these irreversible solid/solid phase transformations resulting from high thermomechanical loads. This metallurgical behavioral model was developed in the framework of continuum thermodynamics with gradients of temperature and internal variables.

scholarly journals Assessment of Thermomechanical Couplings in Tribological Surface Transformations: Application to the Irreversible Near-Surface Solid-Solid Phase Transformations

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Grégory Antoni
Keyword(s):  
Phase Transformations ◽  
Solid Phase ◽  
Thermomechanical Coupling ◽  
Near Surface ◽  
Thermomechanical Couplings ◽  
Coupling Processes

Tribological Surface Transformations (TSTs), which are irreversible near-surface solid-solid phase transformations, tend to occur on railroads frequented by heavy freight trains. The present study is proposed to assess the contribution of thermomechanical coupling processes to the emergence and development of TSTs near the surface of the rails.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

Reactivity in solid phase. Transformations of 2,4-di-tert-butylphenol and its derivatives under elastic deformation conditions

1996 ◽  
Vol 45 (6) ◽  
pp. 1428-1432
Author(s):  
V. B. Vol'eva ◽  
I. S. Belostotskaya ◽  
A. Yu. Karmilov ◽  
N. L. Komissaroya ◽  
V. V. Ershov
Keyword(s):  
Phase Transformations ◽  
Elastic Deformation ◽  
Solid Phase

The growth kinetics of individual ledges during solid-solid phase transformations

1981 ◽  
Vol 378 (1774) ◽  
pp. 351-368 ◽  
Keyword(s):  
Phase Transformations ◽  
Volume Diffusion ◽  
Solid Phase ◽  
Parent Phase ◽  
Steady Motion ◽  
Diffusion Field ◽  
Lateral Growth ◽  
Small Perturbations ◽  
Step Motion ◽  
Kinetics Of

The problem of step motion during lateral growth in solid-solid phase transformations is re-examined. Results are obtained for the steady motion of an individual ledge when volume diffusion in the parent phase is the predominant contribution to the growth rate. A comparison is made between our results and the earlier work of Jones & Trivedi (1971). There are significant differences between the two sets of results particularly in the limit of small perturbations to the Laplacian diffusion field. To confirm the accuracy of the results presented here the calculations have been made by two different methods.

Multiphase Phase-Field Approach for Virtual Melting: A Brief Review

2021 ◽  
Vol 18 (2) ◽  
pp. 102-107
Author(s):  
Arunabha Mohan Roy
Keyword(s):  
Phase Transformations ◽  
Phase Field ◽  
Field Model ◽  
Solid Phase ◽  
Scale Effects ◽  
Phase Field Model ◽  
Short Review ◽  
Nanoscale Material ◽  
Material Parameters ◽  
Field Approach

A short review on a thermodynamically consistent multiphase phase-field approach for virtual melting has been presented. The important outcomes of solid-solid phase transformations via intermediate melt have been discussed for HMX crystal. It is found out that two nanoscale material parameters and solid-melt barrier term in the phase-field model significantly affect the mechanism of PTs, induces nontrivial scale effects, and changes PTs behaviors at the nanoscale during virtual melting.

Sign in / Sign up

Export Citation Format

Share Document