Included and occluded grains in iron single crystals

The paper presents some experimental results concerning the occurrence of stray grains in high-purity iron single crystals grown by the strain-anneal method. The experimental results indicate that the stray grains are either the unabsorbed grains from the polycrystalline matrix with twin orientation or true annealing twins. The iron crystals with a small number of stray grains can be prepared when a steep temperature gradient is used during growth.