EIS and EMIS methods of assessing the fatigue status of a material. The EIS method uses an electrochemical transducer cell to apply electrical perturbations to the material, and to acquire voltage and current measurements over a range of frequencies. The impedance at each frequency is calculated, resulting in impedance spectrum data. This data is correlated to reference data representing the fatigue life of the material. The EMIS method is similar except that mechanical instead of electrical perturbations are applied to the material.