Anomalous strain-energy-driven macroscale translation of grains during nonisothermal annealing

The Optimisation of Hot Isostatic Pressing Treatments for Enhanced Mechanical and Corrosion Performance of Stainless Steel 316l Produced by Laser Powder Bed Fusion

“…Work published by Higgins et al examines the effects of grain growth on microstructures with sub grain structures and non-uniform dislocations/stored energy similar to that in materials prepared by laser powder bed fusion. They detail a bimodal microstructure was observed comprising of noticeably larger and smaller grains similar to that present in conditions 9 -HIP (T 1200 P 200 ) and 11 -HIP (T 1125 P 200 -long hold) [43].…”

Phase-field modeling of stored-energy-driven grain growth with intra-granular variation in dislocation density

“…Higgins et al [16] interpreted this additional energy as the strain energy stored as dislocations, a common term that describes the driving force for recrystallization [17]. They postulated that the stored energy introduced within the grains via the formation of dislocations during the process of non-isothermal annealing would give rise to a driving force for the grains with lower stored energy to consume grains with higher stored energy, leading to the reduction of the total energy.…”

“…A few PF models have been developed to study the influence of anisotropy in grain boundary energy [33], anisotropy in grain boundary mobility [34,35], and second-phase particles [36] on the dynamics of AGG. Higgins et al presented a PF model [16] that extended recrystallization models developed by Moelans et al [37] and Gentry and Thornton [25] to account for the contribution of stored energy as the driving force for grain boundary migration. Their simulations showed that the additional driving force allows for the grains with a low dislocation density to consume the grains with a high dislocation density.…”

“…However, recent imaging experiments (detailed in section 2) suggest that the dislocation density is inhomogeneous even within an individual grain and that the traversed region appears to have a reduced dislocation density, resulting in a variation in the intra-granular dislocation density. In order to capture the effects of these features on microstructure evolution undergoing CHT, it is necessary to extend the PF model presented by Higgins et al [16].…”

Modeling of experimentally observed topological defects inside bulk polycrystals

“…For example, comparisons have been made between observed plastic behaviors and model expectations including twinning [7], grain rotation and breakup [8,9] as well as crack nucleation and propagation [10][11][12]. Studies of thermal responses include recrystallization [13][14][15] coarsening [16][17][18][19] and phase transformations leading to abnormal grain growth [20]. These studies provide direct experimental observations that can and are being used to develop improved models of materials responses.…”