Microstructure and Impact Resistance Analysis of 7075 Aluminum Alloy Modified by FSP

The hot rolled 7075 aluminum alloy was modified by friction stir processing (FSP) technology, and the effects of different processing parameters on impact toughness and microstructure of machining region were analyzed. The results showed that the impact toughness of machining region was 2.3 times that of the base metal when the rotation velocity was 1200 r/min and the feed rate was 60 mm/min, which much higher than base metal. The fracture morphology was observed by using scanning electron microscope and found that the morphology of fracture dimple was uniform and smooth. The grains in the weld nugget zone were obviously refined after friction stir processing, and the grain refinement effects were not the same in different processing parameters.