Tail Departure of Log-Normal Grain Size Distributions in Synthetic Three-Dimensional Microstructures

摘要

Polycrystalline materials are generally thought to have grain size distributions that correspond to log-normal. Statistical volume elements can use such geometric shape distributions to simulate single-phase polycrystals. When the log-normal distribution is used for grain size, however, it can give rise to nonphysical large grains that cannot be practically accommodated in finite simulation volumes. The application of other distributions that afford better control of the upper tails, e.g., truncated distributions, resolves the problem and allows more representative distributions to be generated. These points are illustrated with an example of generation of a synthetic three-dimensional (3-D) microstructure to represent the nickel-based superalloy Inconel 100, which exhibits significant upper tail departure from log-normal. Twin insertion, to represent annealing twins, will also be discussed.