Determination of global mechanical response of friction stir welded plates using local constitutive properties

Global mechanical behaviour, i.e. the true stress-strain curves, yield strength or,, hardening exponents n, and strength coefficients K, of friction stir welded plates, in which the weld line lies either perpendicular or parallel to the axis of the applied tensile force, is determined by using the local constitutive properties of the base metal, heat affected zone and weld nugget. The principle of 'rule of mixtures' is adopted to develop the analytical models. Experimental data from Lockwood (2000 PhD Dissertation Department of Mechanical Engineering, University of South Carolina) for Al 2024-T351 specimens under tension in the transverse direction are compared with the analytical results. The effect of the size of different welding zones on the global mechanical response of the welded plate is also assessed. The 'rule of mixtures' method is shown to be reasonably accurate in determining the global mechanical response of the welded plate.