Relating the kinetics of grain-boundary complexion transitions and abnormal grain growth: A Monte Carlo time-temperature-transformation approach. (15th October 2022)

• Record Type: Journal Article
• Authors: Marvel, C.J.; Riedel, C.; Frazier, W.E.; Rollett, A.D.; Rickman, J.M.; Harmer, M.P.
• Is Part Of: Acta materialia. Volume 239(2022)
• Publication Date: 2022-10-15
• Subjects: Grain-Boundary Complexions -- Grain-Boundary Transformation Kinetics -- Monte CarloSimulation -- Abnormal Grain Growth -- Time-Temperature-Transformation Diagrams; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2022.118262
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Grain boundaries undergo thermally-activated, first-order transitions that result in discontinuous changes of interfacial properties. Importantly, grain boundary transitions lead to changes in bulk material properties ( e.g., embrittlement) and/or behavior ( e.g., abnormal grain growth). Numerous studies have been completed on the equilibrium states of grain boundaries and their transitions ( i.e., complexion transitions), but there have been far fewer investigations of complexion transition kinetics; complexion transitions occur on the atomic-scale and are therefore challenging to detect experimentally. In this work, a 3D Potts grain growth model with stochastic complexion transitions was employed to investigate complexion transition kinetics. A Johnson-Mehl-Avrami-Kolmogorov ( i.e., JMAK) approach was used to extract nucleation and growth rates ( i.e., transformation rates), while point process analyses and correlation functions were used to infer complex interrelated nucleation and growth events. Time-temperature-transformation (TTT) diagrams, in particular grain-boundary complexion, transformed grain, and abnormal grain TTT diagrams, were constructed to summarize the progress of complexion-related transformations. Such diagrams relate complexion-induced grain growth to the underlying complexion transitions and, in the case of abnormal grain growth (AGG), permit one to assess the role of AGG as a temperature-dependent, time-displaced indicator of complexion transitions. Overall, this work details a theoretical framework that can be used to better understand complexion transition kinetics as well as to develop tools for the design of bulk microstructures.