Introducing a thermodynamically consistent formulation for the heat source arising from plastic deformation leads to an additive decomposition of the flow stress into two distinct parts: one associated with dissipation and another linked to the energy stored within the material due to microstructural changes, such as dislocation evolution [1]. This provides a framework for investigating the thermomechanical coupling during plastic deformation. The proposed decomposition provides a structured approach to understanding energy and stress partitioning during plastic deformation of metallic materials. The framework and its implications can be generalized to large deformations and different plasticity models and may serve as a fundamental for studies of dislocation-based thermoplasticity in mono- and polycrystals. In this talk, the framework is motivated and used to analyze experimental data of tensile tests quipped with a thermography camera. Using numerical tools to solve the inverse problem of determining the heat sources due to plasticity [2], this macroscopic method, which is experimentally simple to conduct, provides new insights into microscopic processes and contributes to understanding dislocation evolution during plastic deformation. [1] Böhlke T., Lalović N., Dyck A., Kauffmann A., Heilmaier M., Estrin Y., A thermodynamically motivated decomposition of flow stress in plasticity. [Manuscript submitted for publication]. [2] Chrysochoos A., Louche H., An infrared image processing to analyse the calorific effects accompanying strain localisation. International Journal of Engineering Science, Vol. 38 (16), pp. 1759-1788.