Effect of the Degree of Prior Cold Work on the Grain Volume Distribution and the Rate of Grain Growth of Recrystallized Aluminum

The grain volume distribution of recrystallized aluminum, determined by separating and weighing the individual grains, has been found to be log normal, its spread in size being expressed by the standard deviation of the distribution (In σv), which remains constant during steady state grain growth. The value of In σv is established by the degree of cold working that precedes annealing, being smaller the greater the degree of cold work. Grain growth proceeds the more rapidly the larger the value of In σv that is, the smaller the degree of prior cold work. The distributions of the numbers of faces per grain and of edges per face are also log normal and are proportional to the grain volume distribution. Thus, the relative number of three-edged faces increases with In σv and accounts for the observed increase in the rate of grain growth.