Study On The Temperature Field Distribution And Joint Properties Of 5083 Aluminium Alloy Friction Stir Welding

In the trend of energy saving,green manufacturing and light-weighting,light alloy materials are being used more widely due to their excellent characteristics.Friction stir welding technology is widely used due to its advantages of no fumes,exhaust gases and open flames and the ability to join multiple materials.The heat distribution and process parameters of the welding process directly affect the quality of the joint connection.Therefore,it is essential to investigate the temperature distribution,the combination of process parameters and the mechanical properties of the joint after welding during friction stir welding.The paper selects the widely used 5083 aluminum alloy as the research object,based on thermodynamic theory,using ABAQUS finite element software to simulate the temperature field of the butt joint 5083 aluminum alloy plate with a thickness of3 mm.The temperature distribution in the welding process under different combinations of process parameters is explored.The single factor analysis method is used to study the change law of temperature field in the welding process under different stirring tool rotation speed,welding speed and shoulder amount of pressure,and the process parameter window is reduced according to the temperature required for welding.Further,through the three-factor three-level orthogonal test method,the mechanical properties of the joints are analyzed,the welding process parameters are optimized,and the durability of the specimens under the optimal parameters is studied.The main contents are as follows:(1)The numerical simulation of friction stir welding temperature field for the thickness of 3mm butt joint 5083 aluminum alloy plate is carried out by using ABAQUS finite element software,and the temperature distribution law of the welded joint under different factors are explored by single-factor experimental method.Results found that when the welding speed and rotational speed are constant,with the increase in the amount of pressure on the shoulder,the temperature change in the welding area is small.When the welding speed and the amount of pressure are constant,and with the increase in rotational speed,the friction between the tool and the material becomes larger,the heat generated increases,and the welding temperature gradually increases within a certain range.Under the premise of constant rotational speed and pressure,the heat accumulates more fully when the welding speed is 1mm/s,and the temperature of the welded area is the highest at the same time.(2)Based on the orthogonal test method to study the 5083 aluminum alloy plate stir friction welding process parameters,analysis of the mechanical properties of the joint under different process parameters.In tensile strength and energy absorption value as the response target,through principal component analysis,gray correlation analysis method and mean extreme difference analysis,to obtain the optimal process parameters: rotation speed of 1400r/min,welding speed 1mm/s,the amount of pressure 0.3mm.At this time,the maximum tensile strength of the joint reached225.5MPa,strength reached 95.4% of the strength of the base material,failure displacement of 10.6mm.The response surface method is used to establish a gray correlation based on the welding process parameters of the second-order prediction model.Besides,the accuracy of the prediction model is verified by experiments.(3)Based on the samples prepared by optimizing the process parameters,the corrosion resistance of welded joints is studied by periodic immersion accelerated corrosion test.The cyclic immersion corrosion test shows that the corrosion rate of the joint is low and presents a slow downward trend.Tensile test shows that fracture occurs in the joint part,indicating that the weld core area is the weak area of the test piece.With the extension of the test time,the corrosion points on the surface of the material gradually increased,the corrosion area is expanding,the failure load value and energy absorption value of the joint is decreasing.The failure load value and energy absorption value of the joint tended to decrease.The microscopic morphological observation revealed that the failure form was mostly mixed tough-brittle fracture.