TWI

Friction stir linear welding and friction stir spot welding techniques were employed to fabricate robust and reliable welded joints for automotive front end substructure applications between AA6022-T4 aluminium alloy and AM60B magnesium alloy sheets (thickness 1.5 and 3.1 mm, respectively), and the microstructure and mechanical properties of the weldments were investigated. Specific friction stir welding tools were designed and evaluated for various combinations of process parameters (e.g. tool rotation rate, traverse speed and penetration depth) and different sheet stack-ups. Microstructures were observed by optical microscopy and SEM with energy-dispersive X-ray spectroscopy. An Instron screw-driven testing machine was used to perform lap-shear testing on both spot and linear welds. Issues discussed include the effect of tool geometry on the formation of intermetallic compounds and the interpretation of failure loads in terms of material flow and microstructure.

10th International Symposium, 20-22 May 2014, Session 2B: Dissimilar I, Paper 05