7075铝合金搅拌摩擦焊接头变形行为及等效模型

Deformation Behavior and Equivalent Model of 7075 Aluminum Alloy FSW Joint

利用有限元软件ABAQUS对厚度为6 mm的7075铝合金搅拌摩擦焊(FSW)平板对接接头进行拉伸模拟,通过对不同热输入条件下接头中三轴应力度(σm/σe)的计算,研究了热输入对7075铝合金FSW接头变形的影响规律。在此基础上,建立了7075铝合金FSW接头有限元等效模型。研究结果表明,不同热输入条件下的接头中的三轴应力度突变均发生在TMAZ与HAZ交界处和HAZ与BM交界处;随着热输入增大,三向应力度的最大值升高,最小值减小,7075铝合金FSW接头的屈服强度和抗拉强度均先增大后减小。转速为800 r/min,焊速为300 mm/min,即热输入为2.67 r/mm时是厚度为6 mm的7075铝合金FSW平板对接的最佳焊接工艺参数,此时接头的屈服强度和抗拉强度达到最大值;7075铝合金FSW接头等效模型可以代替精细模型用于后续整车有限元模拟。

The tensile simulation of FSW butt welded joint of 6 mm thick 7075 aluminum alloy plate was carried out by finite element software ABAQUS and the influence laws of heat input on FSW joints deformation of 7075 aluminum alloy were studied through the calculation of the stress triaxiality of the joints under different heat inputs and the finite element equivalent model of FSW joint of 7075 aluminum alloy was established based on this.The results show that,the mutation of the stress triaxiality occurs at the junction of TMAZ and HAZ and the junction of HAZ and BM under different heat inputs.With the increase of the heat input,the maximum value of the stress triaxiality increases,and the minimum value of the stress triaxiality decreases,the yield strength and the tensile strength of the 7075 aluminum alloy FSW joints increase first and then decrease.The best welding parameter of FSW butt joint of 6 mm thick 7075 aluminum alloy plate is the heat input of 2.67 r/mm which is obtained when the rotational speed is 800 r/min,the welding speed is 300 mm/min,and the yield strength and the tensile strength reach the maximum value.The 7075 aluminum alloy FSW joint equivalent model can replace the fine model for subsequent finite element simulation of vehicle.