The macroscopic Schmid’s law and microscopic local strain accommodation mechanism have been widely used to determine the twin variants selection combinedly. In the present study, the selection of \(\left\{ {10\overline{1} 2} \right\}\) twin variants of pure Hf under uniaxial compression was studied with the combined use of electron backscatter diffraction (EBSD) technology and displacement gradient tensor. Results indicated that the initially formed \(\left\{ {10\overline{1} 2} \right\}\) twin variant in one grain adheres to the Schmid’s law, and its appearance modifies the local stress state within the matrix and in neighboring grains. The formation of the following intragranular twin variants and twin pairs at grain boundaries (GBs) was affected by the modified local stress field. For example, the growth and even nucleation of one twin variant can be suppressed by the intragranular local stress induced by the appearance of its para-position twin; paired \(\left\{ {10\overline{1} 2} \right\}\) twins can be generated at GB if one of the twin variants is able to accommodate the local stress caused by twin impingement on GB in its neighboring grain. For the twin pairs at GBs, the value of misorientation angle between two neighboring grains determines whether the incoming twins can transfer across the GB or be blocked by the GB, and this threshold is 33° in the present study.
