AbstractThe problem of interest is grain-size-dependent hardening in polycrystalline metals. We study the multiphysics problem of heat conduction coupled to gradient crystal plasticity and investigate the temperature field on the grain level for adiabatic loading. The underlying equations for the thermomechanical coupling are derived for a crystal plasticity model with gradient hardening. The influence of the temperature field on misorientation of the slip directions between adjacent grains is investigated. Additionally, the influence of the loading velocity and the size of the grain structure are examined. Numerical simulations are presented and analyzed.