IDENTIFICATION OF ENERGETIC AND DISSIPATIVE FLOW STRESS USING INFRARED THERMOGRAPHY

Based on own continuum-thermomechanical considerations extending, not only the energy stored and dissipated during plastic deformation of metals can be determined using infrared thermography (IRT), but also the flow stress can be additively separated into an energetic and dissipative component. An experimental-numerical methodology as well as some results for oxygenfree copper Cu-OF in pre-deformed and recrystallized condition are presented. A custom tensile setup, high-resolution thermal imaging, and a dedicated image processing routine enabled spatially and temporally resolved reconstruction of deformation-induced heat sources, accurate evaluation of the heat conduction equation and subsequent stress partitioning. The results show that both stress components evolve with plastic strain and are path-dependent, challenging the assumption of constant dissipative stress. The Taylor-Quinney factor derived directly from experimental data remained relatively stable during monotonic loading. Overall, the method provides a robust, non-invasive approach for quantifying internal energy storage and validating thermomechanically consistent constitutive models, offering new experimental insights into the coupling between mechanical work and thermal dissipation. The method’s potential to infer microstructural evolution from macroscopic measurements represents a promising direction for future research.