Investigation on underwater FSP of Al-Mg-Si alloy surface composites

Abstract

In present research, parametric effects of underwater friction stir processing (UWFSP) upon microstructural and mechanical properties is investigated for AA6082/SiC surface composites. Experimental design was accomplished using Taguchi technique and three factors at three levels each were utilized. These factors include- rotational speed of tool, traverse speed of tool and tool shoulder diameter. Responses such as microhardness, ultimate tensile strength (UTS), yield strength (YS) and percentage elongation (%EL) are modeled using regression analysis based on Taguchi’s orthogonal array design of experiment. Optimum combinations of process parameters were determined for the selected responses. It was found that each of three process parameters significantly affects the responses. Tool shoulder diameter is found most significant parameter affecting microhardness, YS, and %EL. However, rotational speed of tool is found most significant parameter affecting the UTS. An enhancement of ∼27% in microhardness was achieved at optimum condition. The study on microstructural evolution and examination of dispersion of reinforcement particles was carried out with the aid of optical microscope. Results revealed that at optimum combination of process parameters, uniform dispersion of reinforcement particles and enhanced mechanical properties were achieved. Conclusions of this research clearly correlate observations with mechanical properties and microstructural evolution.