The effect of initial grain size distribution on abnormal grain growth in single-phase materials

A model that describes the temporal evolution of an initial grain size distribution (GSD) has been used to analyze the effect of initial GSD on grain growth. Based upon the work of Hillert, and Hunderi and Ryum, this model uses a finite difference technique to numerically solve the continuity equation. A formal method has been developed to create synthetic GSDs. The model is used to study the evolution of both continuous and discontinuous GSDs. For either case, two parameters describe the deviation from steady state: u(max) is the ratio of the largest grain radius to the critical grain radius, and F-o is the initial fraction of grains larger than twice the critical radius. The analysis is applied to lognormal GSDs obtained from experimental results. It is shown that, for all initial GSDs with nonzero F-o, a transient period of abnormal grain growth characterizes the initial stages of growth. F-o and u(max) allow approximate prediction of the duration and extent of abnormal grain growth. (C) 1998 AL ra Metallurgica Inc. Published bl Elsevier Science Ltd. All rights reserved.