<p>We demonstrate the existence of proportional-stress points in cantilevers, located approximately two-thirds of the cantilever’s half-thickness away from the neutral axis toward the outer fibers, where the stress state under an applied moment remains effectively linearly elastic, even as the material undergoes plastic deformation. In other words, the stress redistribution occurring during plastic flow does not alter the stress state at these specific locations. Building on this finding, we develop a method that utilizes proportional-stress points and strain measurements acquired via digital image correlation (DIC) along the cantilever’s length to extract key plastic flow parameters, including yield strength, strain hardening exponent, strain hardening coefficient, and strain rate sensitivity, from a single test&#xa0;performed using a single specimen. Experiments on commercially pure copper demonstrate that yield strength, strain hardening coefficient, and strain hardening exponent can be simultaneously estimated in both tensile and compressive regions with high statistical reliability and accuracies of 90%, 100%, and 99.5%, respectively. Moreover, the strain rate sensitivity of copper can be accurately determined from a single DIC-augmented-bending test performed at a constant displacement rate, highlighting the high-throughput potential of the method. Also, we discuss challenges inherent to the proposed approach, particularly the dependence of the proportional-stress point location on material parameters unknown <i>a priori</i> as well as limitations related to the imaging setup and DIC resolution, and a way forward.</p> Graphical abstract <p></p>