This dataset supports the manuscript currently titled:“Plastic work partitioning during slip- and twinning-dominated deformation in AZ31B magnesium alloy.” Previously posted on arXiv (v1) as:“Slip- and twinning-related dissipation in AZ31B magnesium alloy.” No changes to the data files have been made in this version. It contains the numerical data used to generate all figures presented in the manuscript.An HDF5 file is provided with time-resolved, spatially coupled fields obtained from synchronized digital image correlation (DIC) and infrared thermography (IRT) analyses. Additionally, electron backscatter diffraction (EBSD) maps of the deformed material (in *.ang format) are included.The data cover two specimen geometries: samples cut parallel and perpendicular to the extrusion direction (ED).All files are intended to support reproducibility and further quantitative analysis of deformation and dissipation mechanisms. A detailed description of the HDF5 file structure is available at https://thermocorr.ippt.pan.pl/output-file-structure.html