Analysis of micro-friction stir welding surfaces using fractal methodologies

Abstract

Abstract The weld surface produced by micro-friction stir welding (micro-FSW) exhibit multi-scale nature. The surface topography of weld surfaces affects the overall strength of components and significantly changes with process parameters. In this work, multi-scale surface characterization techniques are used to study the surface topography of micro-FSW surfaces. The relation between process parameters and topography parameters is discussed in detail. Length-scale fractal analysis is employed on micro-FSW surfaces, and it is concluded that surface complexity increases with an increase in tool rotational speed. Within the range of process parameters studied, smoothening takes place at higher tool feed. The Hurst coefficient (H), which is an important descriptor of fractal geometry is found to increase with an increase in tool feed.