The effect of friction stir welding tool wear on the weld quality of aluminum alloy AMg5M

Abstract

Friction stir welding (FSW) tool wear has been studied from the standpoint of tribological layer generation and interaction of this layer with the tool’s metal. It was shown that during FSW on aluminum alloy the latter adheres to the tool’s working surface and then iron/aluminum reaction diffusion is initiated under the conditions of high mechanical stress and temperature. Since diffusion along the former austenite grain boundaries is much faster than volume diffusion, an intermetallic compound is formed inside the tool’s metal thus causing embrittlement and pulling out the tool’s metal fragments.