Aluminum Alloy Plate Vsr Micro-yield Mechanism Of The Pilot Study

Vibration Stress Relief (VSR) has been proved to be an effective residual stress reduction technique in practice. However, it is found that the effects of stress reduction to different materials and components are not the same in applications, so it is necessary to study the mechanism of VSR to improve the application in production process. In this paper, through experimental researches, general laws of the evolution of residual stress in the aluminum alloy plate under cyclic loading were obtained, and the mechanism of VSR was analyzed and discussed.In this paper, the electrolytic etching and polishing process and measurement technique of X-ray diffraction method for aluminum alloy plate were optimized. The surface residual stresses of aluminum alloy plate after quenching were measured and the distribution laws and range were obtained.Secondly, by means of experiments, the surface residual stress evolutions in the following two conditions were studied:the sum of load stress and residual stress exceeded the local yield stress or not. When the stress exceeded the yield stress, the residual stress can be reduced, the evolution laws accord to plastic deformation mechanism and work hardening, then if not, there are two conditions. When less than a certain value, the cyclic loading can not affect the residual stress, when exceeded this value, after a certain period of cyclic loading, residual stress can be reduced, and the amplitude of the load stress is positively effect to the reduction. In addition, the residual stress in sand blasting samples can be significantly reduced than quenching samples, so the stress relief is also related to the initial residual stress condition and stress gradient.Thirdly, the mechanisms of VSR were deeply discussed. Respectively based on the Bauschinger effect and dislocation theory, the macro and micro mechanisms of VSR were summarized, and the mathematical models and empirical formulas in the reduction of residual stress were presented. Based on the creep theory, the mechanical relationship of VSR and cyclic creep was discussed, and common factors such as stress amplitude, temperature and material properties were analyzed. Based on the principle of strain energy, the relationship between residual stress field and the energy state was discussed and the stress relaxation in VSR was studied from the perspective of energy conversion.Finally, it is also found that VSR can relief the peak stress and have a good effect to the dimensional stability of quenching aluminum alloy plate in another comparing experiment, and the mechanism was discussed.