| In this paper, the thickness of 4mm plates of 1060-Y2,6061-T4,5052-H32 and 2024-T351 aluminum alloys were welded by friction stir welding used a cylindrical tool with left-hand thread. Through the mechanical properties of the material was changed to be welded,Study effect of material properties on optimal parameters, plastic metal flow rule, the joint mechanical properties. Analysis the influence of the mechanical properties of the material on the quality of weld joints, optimize the joint performance for stir friction welding process parameters provide a theoretical basis for prediction.The results shows that the rotational speed of the tool and welding speed play a vital role on effect the FSW weld; moderate-intensity and low hardness of aluminum alloy friction stir welding, in a wide tool head rotation speed and welding speed can get a good appearence inside the organization defect-free welds and obtain excellent joint performance within a certain range of process parameters, Joint strength increased first and then decreased with the increase of tool rotation speed or stir welding speed. The mathematical model can be established for effectively predict the ideal parameters.Using the same kind of wrought aluminum alloy friction stir welding, Large nugget width and height showed a decreasing trend after the first increase with increasing welding speed and rotation speed of the tool. the weld nugget. Advance side cross-sectional height Ha, Retreat side height Hr and the greater the width W in the thickness direction "aspirate- squeezing" effect with increases of enhanced material properties with the increase of tensile strength and hardness values of the material being welded. While relatively high joint strength, the largest nugget under optimal parameters. It’s appear "hook" ditch after friction stir welding of dissimilar materials, nugget area and disordered region mainly based materials harder edge forward.In the preferred process parameters,Joint fracture location in the forward side of the heat and machine affect zone and heat affected zone at the junction, Clad layer present on the surface will make the fracture occurs in the nugget and heat and machine affected zone at the junction of the machine; The second phase reunite and inhomogeneity at the reunion is the main cause of weak point of joints. Toughness fracture are the main fracture form. The existence a fitting linear relationship between the mechanical properties of the base metal and joints, The strength and hardness of joints are more than 80% of the base material; Grain refinement is excellent friction stir welded aluminum head of the main performance. And the higher the hardness and strength of the base material, the more serious their joint performance loss,after friction stir welding.By others mechanical properties of aluminum alloy friction stir welding for the mathematical model is validated, The difference of the results of experimental data and mathematical models is very small, Predict the joint strength can be controlled within 2%. This is to ensure the safe use of welded components played a crucial role. For friction stir welding technology to provide a reference value in the aerospace component of the application. |
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