Microstructure and Mechanical Properties of Friction Stir Welded Al-Zn-Mg-Cu Alloy
The microstructure and mechanical properties of friction stir welded Al-Zn-Mg-Cu alloy sheet were investigated by means of hardness and tensile tests, optical microscope and scanning electron microscope. The hardness profile of the weld exhibits a W shape with the lowest value in the thermo-mechanically affected zone on the advancing side. The tensile strength and elongation of the weld are about 71% and 72% that of the base material. In the nugget zone, there are a number of fine recrystallized grains and dispersed precipitates at grain boundaries. In the thermo-mechanically affected zone, the grain size is not uniform and there are a number of precipitates at grain boundaries. In the heat affected zone, the grain structure is similar to the base material.
S. D. Liu et al., "Microstructure and Mechanical Properties of Friction Stir Welded Al-Zn-Mg-Cu Alloy", Applied Mechanics and Materials, Vol. 628, pp. 7-11, 2014