Three-dimensional analysis of grain topology and interface curvature in a β-titanium alloy

While considerable efforts have been made to model the effects of grain coarsening, there has been little experimental verification of these models. Using serial sectioning techniques, the full 3-D morphology of 2098 β-titanium grains in Ti–21S are analyzed and directly compared to grain coarsening theories. The experimental grain size distribution and the distribution in the number of grain faces are shown to have a close comparison to the predictions of the steady-state size distribution from a number of simulations and analytical theories. The geometric factor of the growth rates is determined by measuring the mean curvature of the grain faces. It is found that, on average, the grains with an average of 15.5 faces have a zero integral mean curvature of the grain faces, higher than the predicted value of 13.4 faces. This difference is suggested to be due to the non-random nearest-neighbor effects within the grain network.