Dauphiné twinning in polycrystalline quartz

A recently developed crystal based continuum model for twinning and phase transformations is successfully applied to Dauphiné twinning and the α (trigonal) ↔ β (hexagonal) phase transformation in quartz. Both finite element and uniform deformation simulations are performed of quartz polycrystals and several experimentally observed phenomena are qualitatively reproduced. Results are given for mechanically induced twinning and texture memory during phase transformation. The results highlight the importance of local stress variations due to grain interactions. Due to the form of the driving force, twinning is particularly sensitive to local stress variations.