Dataset: High-temperature micropillar compression data for Nickel bicrystals with a high-angle grain boundary

This dataset contains SEM images and in situ SEM micropillar compression data from 30 micropillars fabricated in a Ni bicrystal containing a high-angle grain boundary. The pillar diameters range from 1 µm to 3 µm, and tests were performed at room temperature and at 300 °C under a nominal strain rate of 10^{-3} s^{-1}. Micropillar compression tests were performed using a Bruker Hysitron PI89 indenter equipped with a high-load transducer and operated in displacement-controlled mode.Data are organized by pillar diameter and test temperature. Each group includes SEM images acquired before and after deformation, documenting pillar geometry and the resulting slip activity. The corresponding engineering stress–strain data from the in situ compression tests are provided in CSV format.