Study on the influence of process parameters of severe surface mechanical treatment process on the surface properties of AA7075 T651 using TOPSIS and Taguchi analysis

Abstract

This article investigate the mechanical and wear characteristics of AA 7075 T651 alloy subjected to severe surface mechanical treatments(SSMT). The Taguchi orthogonal array and Analysis of variance are employed in identifying the influence of process parameters and their significant contribution. A Multi-criteria decision making process is adopted to identify the ideal condition for characterization analysis. The optimal value ascertained is the usage of shot diameter of 8 mm, 60 min of treatment duration and speed of revolution at 1000 rpm. It is identified that the shot diameter is the major contributing factor in improving the wear and hardness of the specimen. A maximum hardness of 235 HV is obtained with an average deformed layer thickness of 350 μm in the optimal condition. Further, the ultimate tensile strength value of 637 MPa and wear rate of 2.77 × 10–6 g m−1 is observed. The x-ray diffraction (XRD) analysis divulged an increment of 83.22% in the compressive residual stress introduced during the treatment with SSMT process. This abate corrosion rate by 17.77%. The enhancement in the wear and corrosion resistance is ascribed to the introduction of compressive residual stress and dislocation strengthening during SSMT process