Thermodynamics of Configurational Remanence: Fictive Stress and the Phase Reset of Structural Fatigue

Classical thermodynamics treats phase transitions using strictly state-dependent variables, treating structural fatigue in solids as decoupled from chemical thermodynamic limits. This paper proposes a thermodynamic framework that bridges fracture mechanics and physical chemistry by introducing Configurational Remanence (J), a path-dependent extensive variable representing volumetric microscopic defects, and its conjugate intensive variable, Fictive Stress (Ψ). We modify the First Law of Thermodynamics to account fortrapped configurational work and hypothesize a ”phase reset” phenomenon where accumulated structural fatigue reduces the enthalpy of vaporization. Quantitative modeling of heavily cold-worked FCC metals (Copper and Aluminum) predicts a stored molar defect energy of ∼ 11 J mol^(−1). We propose an experimental protocol using high-resolution Differential Scanning Calorimetry (DSC) to measure this latent energy shift.