PNNL

Abstract

Friction Stir Interlocking (FSI) has been applied for joining dissimilar materials with different physical, chemical and mechanical properties. The FSI process combines friction stir welding with mechanical interlocking where two dissimilar sheets are joined in a lap configuration using a third body interlock. In the present study, AZ31 magnesium alloy and carbon fiber reinforced polymer (CFRP) sheets with a thermoplastic matrix were lap joined through FSI with AZ31 interlocks. Microstructural characterization of the FSI joint showed that AZ31 magnesium sheet was mixed sufficiently with AZ31 interlocks, effectively joining CFRP to the AZ31 sheet. Lap shear tensile testing showed that the load capacity of FSI joints ranged from ~80-100 N/mm with fracture occurring within the CFRP around AZ31 interlocks. Finite element analysis was conducted to simulate the lap shear tensile testing for different FSI configurations. The simulation results are in good agreements with the experimental data and observations in terms of both load-displacement curve and CFRP fracture occurring path.