Microfaceting in a tungsten incoherent twin boundary

Abstract
Experiments are described in which the field‐ion microscope is used to observe the details of grain‐boundary migration in polycrystalline tungsten. Annealing is done in situ and the specimen is observed prior to and after several heating pulses. Microfacets are formed during the process which after analysis are observed to differ from those expected when the coincidence site lattice model is assumed to be valid.