Temperature hysteresis of the order-disorder transition in carbon-supersaturated α-Fe

• Published in: Physical review. B, Condensed matter and materials physics Vol. 96; no. 21; p. 214104
• Main Authors: Maugis, Philippe, Danoix, F., Zapolsky, Helena, Cazottes, Sophie, Gouné, Mohamed
• Format: Journal Article
• Language: English
• Published: American Physical Society 01-12-2017
• Subjects: Chemical Sciences; Condensed Matter; Material chemistry; Materials Science; Physics
• ISSN: 1098-0121; 1550-235X
• DOI: 10.1103/PhysRevB.96.214104

Although many works have been devoted to the order-disorder transition in carbon-supersaturated α-Fe, all seem to have overlooked the temperature hysteresis phenomenon occurring around the critical temperature. It is shown, from a mean-field model based on the elasticity theory of point defects, that the origin of the temperature hysteresis is thermodynamic. As a consequence, both the critical temperature and carbon concentration for the order-disorder transition can be defined upon heating and cooling. The results obtained were successfully compared to molecular dynamics simulations, and are evidence that the transition is of first order and that linear elasticity is the predominant source of the thermodynamics of the Fe-C solid solutions.