| With the enhanced consciousness of energy shortage and environmental protection of human being, Decreasing the oil consumption by automobile and offgas that harmful to environment had drawn more and more attention from the public, lighten the weight of automobile is one of the most effective methods by increasing the proportion of light,high strength materials in automobile industry. Friction stir welding (FSW) used in our paper is a late-model solid phase welding method, many studies were carried out as follow:(1) To determine the difference of FSW and fusion welding, Friction stir welding and TIG were carried out on 1060 aluminum. The influence of process on microstructure evolution, mechanical properties and fracture morphologies of aluminum alloy friction stir and TIG welds were analyzed.(2) The aluminum alloy 5A02 plate was successfully friction-stir welded at different parameters. Mechanical properties of joints for friction stir welds were obtained. Welding quality graph based on matrix system for friction stir welds were obtained. The effect of process parameter on welding quality was deduced from quality graph which can conduct production and optimize parameters. The effect of ratio between rotation speed and welding speed on quality can been seen.(3) The friction stir welding of dissimilar MB3 magnesium alloy and 1060 aluminum was carried out. The profile, mechanical properties and fracture morphologies were analyzed.(4) The scan image of friction stir weld for 1060 aluminum was obtained by ultrasonic C-scan imaging method. The variation trend in the depth direction was deduced by studying on internal appearance characteristic under the different craft parameter condition.(5) The fatigue strength of friction stir and TIG welds by up and down method under certain life was carried out. Microstructure evolution and influence factor of joints were analyzed.
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