Numerical modeling of dissimilar materials – Al 6061-T6 and AZ31

Joining of dissimilar materials Al6061-T6 and AZ31 alloy using FSW reveals lamellar and chaotic intermixing. Thermo-physical properties of the stir zone are experimentally measured which is not an average value of the base alloys but exhibit a complex relationship with the microstructural features and the intermixing of Al and Mg in the weld region. The numerical model is developed using actual thermo-physical properties of the stir zone to predict the temperature distribution on the advancing and retreating side. Thermal cycle and peak temperature are computed for average as well as measured thermo-physical properties using 24 mm, 20 mm and 16 mm tool shoulder diameter. A good agreement between the results is obtained for actual thermo-physical properties of the stir zone.