The constitutive relations of Maxwell's equations rest on a silent assumption: the material does not change. The green energy transition is pushing it to its limit, as extreme stresses progressively, irreversibly degrade the material. Yet current constitutive frameworks fail to capture how the electromagnetic behavior of magnetic components evolves as the material degrades.

Addressing this question requires bridging electromagnetics, materials science, and power electronics. We will resolve constitutive evolution through accelerated aging at Aalborg University and uncover underlying degradation mechanisms through advanced characterization at Oxford. Linking what changes to why it changes enables a reformulated constitutive framework in Maxwell's equations.