摘要
对厚3 mm的2024铝合金薄板搅拌摩擦焊接头微观组织和力学性能进行了研究。结果表明,在旋转速度为800r/min,焊接速度为300 mm/min时,接头抗拉强度Rm,屈服强度ReL和伸长率A分别达到461 MPa、332 MPa和14.6%,接头强度可达母材的94.8%,屈服强度可达母材的87.5%;接头存在3个组织变化区,其中焊核区内发生动态再结晶,生成细小的等轴晶粒,热影响区发生了回复、再结晶和粗化,为扁平状组织;微观断口中存在大量的浅韧窝和撕裂棱,表现出良好的塑韧性;接头横截面、上表面的硬度的最低值均出现在热影响区和热力影响区之间;焊核区的晶粒尺寸最小,影响区晶粒和第二相粒子得到明显细化,合金中的第二相粒子主要为棒状的Al2CuMg(S相)和颗粒状的Cu Al2(θ相)。
Microstructures and mechanical properties of the whole specimen in the 2024 aluminium alloy thin plate joint obtained by friction stir welding(FSW) were studied.The results show that the tensile strength Rm、yield strength ReL and elongation A reaches 461 MPa,332 MPa and 14.6% when the rotating speed is 800 r/min and the welding speed is 300 mm/min.The weld joints consist of three different zones,the nugget zone consists of fine equiaxed grains,and the affected zone consists of flat and nubby grains.The fracture morphologies show that there are lots of low mesh dimples,and the fracture mode is toughness-brittle type.The profile of hardness traverses across and the upper of the joint exhibits like 'W'and that the heat-affect zone(HAZ) has serious softening.Compared with base metal,microstructures in the nugget contains equiaxed grains,the affected zone grain and second-phase particle is more homogeneous and small.The second-phase particle are mainly composed of Al2CuMg(S phase) and Cu Al2(θ phase).
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2013年第S2期423-427,共5页
Rare Metal Materials and Engineering
基金
国防基金(KZ101302117)
关键词
搅拌摩擦焊
2024铝合金
微观组织
力学性能
friction stir welding
2024 aluminum alloy
microstructure
mechanical property
