几何参数对2219铝合金拉拔式摩擦塞补焊接头微观组织及力学性能的影响EI北大核心CSCD

拉拔式摩擦塞补焊是火箭贮箱制造过程的重要技术之一。研究8 mm厚2219-T87铝合金拉拔式摩擦塞补焊接头的几何形状及其对接头微观组织和力学性能的影响。结果表明:塞孔及成形环几何形状对接头界面结合质量有重要影响。当焊接工艺参数为7000 r·min^(-1)主轴转速,35 kN轴向拉力以及16 mm轴向进给量时,使用锥直孔塞孔可有效防止塞棒在焊接过程中发生颈缩,从而消除接头未焊合缺陷;使用阶梯孔形成形环可以改善接头界面受力状态,防止弱结合缺陷产生。微观组织分析表明,毗邻结合界面的母材侧组织发生动态再结晶,热机械影响区组织发生明显塑性变形。接头附近组织受焊接热循环和塞棒旋转挤压作用发生明显软化,硬度最低值出现在热机械影响区,约为90HV。当接头存在焊接缺陷时,接头抗拉强度及伸长率较母材大幅降低,而无缺陷焊接接头的抗拉强度及伸长率分别为360.1 MPa和6.45%,接头系数为0.828,断裂方式为韧性断裂。

Influence of geometric parameters on microstructure and mechanical properties of friction pull plug welding joints for 2219 aluminum alloy

Friction pull plug welding is one of the key technologies in the manufacturing process of rocket tank.The geometrical shape and its effect on microstructure and mechanical properties of friction pull plug welding for the 8 mm thick 2219-T87 aluminum alloy were studied.The results show that the geometry of hole and forming ring has an important effect on the interface quality of the joint.When the welding parameters are 7000 r·min^-1 rotation speed,35 kN axial tensile force and 16 mm axial feed,the use of tapered straight hole can effectively prevent the neck of plug during the welding process,so as to eliminate the lack of bonding defect.The stepped shaped forming ring can improve the stress state of interface and prevent the weak bonding defects.The microstructure analysis shows that dynamic recrystallization occurs at the base material side adjacent to the interface,and obvious plastic deformation occurs at the thermo-mechanical affected zone.The microstructure adjacent to the bonding interface is obviously softened by the welding thermal cycle and the rotary extrusion of the plug;and the lowest hardness value is about 90HV,which occurs in the thermal mechanical affected zone.When the joint has weld defects,the tensile strength of the joint significantly reduces compared with that of base material.The tensile strength and elongation of the joint without weld defects can reach 360.1 MPa and 6.45%,respectively,the joint coefficient is 0.828,and the fracture mode is ductile fracture.