The influence of track overlap value during multi-pass friction stir processing of a conductive AD31 alloy busbar

Abstract

This paper examines the influence of track overlap value during friction stir processing (FSP) on the microstructure and properties of a busbar made of AD31T aluminium alloy. In particular, the influence of 6 parallel tracks with an overlap of 10 mm and 5 mm on the formation of structure and volumetric defects in the volume of the stir zone was studied. It has been shown that carrying out FSP at a tool rotation speed of 1120 rpm and a linear tool speed of 200 mm/min ensures the absence of macroscopic defects in the volume of the treated area in both cases. Reducing the amount of overlap to 5 mm made it possible to achieve the formation of a homogeneous structure and the absence of untreated zones. This type of processing, with given tool geometry and FSP regimes, can be recommended as a method for processing the surface and subsurface layer of aluminium alloys to increase their hardness without significant loss of their electrical conductivity.