Analytical modelling of grain growth in metals and alloys in the presence of growing and dissolving precipitates—II. Abnormal grain growth

Abstract

The present investigation is concerned with analytical modelling of grain growth in metals and alloys in the presence of growing and dissolving precipitates. In Part II the modelling methodology presented in Part I for normal grain growth has been further developed and applied to abnormal grain growth. The judicious construction of the constitutive equations makes full use of both dimensionless parameters and calibration techniques to eliminate poorly known kinetic constants. The results are presented in the form of novel “mechanism” maps (by utilizing the concept of group variables) which show the competition between the various processes that lead to abnormal grain growth during heat treatment. This approach has made it possible to fit many of the apparently conflicting results into a more consistent picture and establish a simple criterion for the initiation of abnormal grain growth under different pinning conditions. It is concluded that the key to a verified, quantitative understanding of the phenomenon of abnormal grain growth lies primarily in the recognition of the important effect of precipitate stability on the secondary recrystallization kinetics.