6005A-T6铝合金型材静轴肩搅拌摩擦焊接头微观组织与力学性能

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Abstract： A 6Oo5A-T6 aluminum aloy sections was subjected to stationary shoulder friction stir welding.The microstructure and mechanical properties of butt-lap joints produced by stationary shoulder friction stir welding were investigated using anoptical microscope，microhardness tester，electronicuniversal testing machine and highfrequency fatigue testing machine.The results demonstrate that the microstructure of the but-lap joint in the stir Zone was occurrd dynamic recrystallization，resulting in the formation of fine equiaxed grains with an average size of approximately . In contrast，the grain size in the heat affected zone was significantly larger，reaching an average of about 1 0 0 μ m .The results of the hardness test indicate that the hardness of joint exhibits a“W” distribution patern.Themean yield strength，ultimate tensilestrength and elongation of the welded joints were found to be ，191MPaand 3 . 5 3 % ，respectively. It was observed that all the joint tensile specimens fractured in the heat afected zone.The median fatigue limit of the joint under the condition of cycles is 1 1 2 M P a ，while the lower fatigue limit of the joint is when the confidence level is 9 5 % and theprobabilityof failure is 5 % . This study provides fundamental theoretical data for the application of stationary shoulder friction stir welding technology in the manufacturing of aluminum alloy car bodies.

Keywords： stationary shoulder friction stir welding; 6Oo5A-T6 aluminum alloy; microstructure; mechanical properties

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2 试验材料与方法

搅拌摩擦焊（FrictionStirWelding，FSW）技术自问世以来，已展现出广阔的应用前景，在工程上也得到了广泛应用[1-3]。（剩余7556字）