Comparison of the thermal and vibrational stress relief methods in terms of mechanical and metallurgical aspects of rolled AA2024 specimens

Abstract

Vibrational stress relief (VSR) and thermal stress relief (TSR) are among the most common treatments after manufacturing processes to enhance the mechanical and metallurgical qualities of the products. Residual stress relief is of the important purposes for such treatments. In this study VSR and TSR treatments are compared regarding the mechanical and metallurgical properties of cold rolled AA2024 specimens. VSR and TSR treatments are separately performed on the identical cold rolled specimens after which dimensional distortion, tensile strength, hardness, and microstructure are evaluated on the specimens while residual stress has been analyzed in finite element model. According to the results, VSR treatment has had better performance in the field of distortion reduction, tensile strength, and elasticity modulus by 25.00%, 2.21%, and 2.98% respectively, while TSR had a slightly more constructive effect on hardness by 2.91%. These could be due to the metallurgical slight effect of stable grain size and shape in VSR versus minor grain growth for TSR. Finite element analysis results have also demonstrated the average reduction of the equivalent residual stress about 31% after TSR treatment, and about 42% after VSR treatment. Grain shape has been influenced slightly by VSR due to minor plastic deformations during mechanical vibration compared to TSR, while grain size has been observed to be slightly more in TSR due to minor grain growth.