|About this Abstract
||2010 TMS Annual Meeting & Exhibition
||Computational Thermodynamics and Kinetics
||Grain Growth Stagnation due to Grain Boundary Roughening
||Elizabeth Holm, Stephen Foiles
|On-Site Speaker (Planned)
The thermodynamic equilibrium state of crystalline materials is a single crystal; however, polycrystalline grain growth almost always stops before this state is reached. While typically attributed to solute drag, stagnation occurs even in high purity materials. Molecular dynamics (MD) simulations indicate that boundaries undergo thermal roughening associated with an abrupt mobility change. At typical annealing temperatures polycrystals will contain both smooth (slow) and rough (fast) boundaries. When the roughening transition is included in a mesoscale grain growth model, even small fractions of smooth, slow boundaries stop grain growth, with the final grain size dependent on the smooth boundary fraction. In MD simulations of atomic-scale polycrystals, grain radius initially increases with the square root of time and then slows dramatically at a characteristic grain radius, in quantitative agreement with the mesoscale model predictions. We conclude that grain boundary roughening provides an alternate stagnation mechanism that applies even to high purity materials.
||Definite: A CD-only volume