Solid-state phase transformation kinetics in the near-equilibrium regime

• Published in: Journal of materials science Vol. 50; no. 2; pp. 662 - 677
• Main Authors: Jiang, Yi-Hui, Liu, Feng, Wang, Jin-Cheng, Zhang, Zhong-Hua
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.01.2015; Springer; Springer Nature B.V
• Subjects: Alloys; Analysis; Binary alloys; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; cobalt; Cobalt base alloys; Crystallography and Scattering Methods; Dilatometry; Equilibrium; Ferrous alloys; Iron; Kinetics; manganese; Manganese base alloys; Materials Science; Mathematical models; Phase transformations; phase transition; Phase transitions; Polymer Sciences; Solid Mechanics; Solid state; Temperature dependence; Thermodynamic equilibrium; Thermodynamics; Transformations; Continuous Nucleation; Isothermal Transformation; Thermodynamic Term; Transformation Kinetic; Gibbs Energy Balance
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8625-1

Solid-state phase transformation kinetics in the near-equilibrium regime behaves differently from that in extremely non-equilibrium regime since their thermodynamic states are different. Incorporating temperature- and transformed fraction-dependent thermodynamic terms, a thermo-kinetic model is derived to describe the transformation kinetics in the near-equilibrium regime. The model predicts a sluggish stage in isothermally conducted transformation and a temperature-dependent stage in non-isothermally conducted transformation. Then, the kinetics of γ / α transformations in two binary substitutional Fe-based alloys (i.e. Fe-3.28 at.% Mn and Fe-1.73 at.% Co), measured by isothermal and non-isothermal dilatometry, is investigated by the newly proposed model. The model quantitatively describes the retarded isothermal kinetics in Fe-3.28 at.% Mn alloy and the abnormal non-isothermal kinetics in Fe-1.73 at.% Co alloy.