Tool geometry effect on the characteristics of dissimilar friction stir spot welded bulk metallic glass to lightweight alloys

A small-scale joining technique for dissimilar friction stir spot welding (FSSW) of a BMG alloy to lightweight crystalline alloys has been developed. An experimental apparatus which could possible give a precise control of the friction time, the plunge speed and the plunge depth of the tool was used. In this study, the influences of tool geometry with different pin shape on the joining characteristics and on the failure load of specimens after dissimilar FSSW were investigated. As a result, it was found that the tool geometry influenced on the welding performance of the BMG alloy to lightweight crystalline alloys at small tool plunge depth and the extent of BMG particles penetrated onto the lightweight alloy side, especially for the Mg alloy/BMG material combination.