Abstract <p>The paper presents the results of works on a study of surface hardening of flat samples made of an aluminum alloy and corrosion-resistant steel in a cyclic compression mode without accumulation of unilateral plastic deformation. Processes of fabrication of the samples, mechanical properties of the initial semifabricated products, and procedures for their hardening are described, and the results of fatigue tests are shown. Conditions of plastic introduction of punches are considered, and it is experimentally shown that hardening is carried out in a region of macroscopic elastic deformations. Possible mechanisms of hardening are analyzed, and it is shown that the main acting factor of the hardening process is fatigue hardening.</p>