喷射成形7055铝合金激光焊接头组织性能研究

发布时间：2018-06-06 14:39

本文选题：铝合金 + 喷射成形　；参考：《稀有金属》2017年07期

【摘要】：采用激光焊接方法对2 mm厚喷射成形的7055铝合金进行了焊接实验。通过背散射电子衍射技术(EBSD)、扫描电镜(SEM)、能谱仪(EDS)、透射电镜(TEM)、显微硬度和室温拉伸试验等测试方法对焊接接头的微观组织和力学性能进行了分析。结果表明:7055铝合金激光焊接头热影响区无明显的软化,焊缝显微硬度最低,约为母材的77%,接头的抗拉强度和伸长率分别约为母材的61%和4.1%。热影响区观察到发生了再结晶的等轴晶粒,但晶内可观察到弥散的η'相;熔合线附近形成了晶粒取向随机分布的细小的等轴非枝晶区;焊缝区靠近熔合线为柱状枝晶,靠近焊缝中心为胞状枝晶,晶内无弥散强化相。综上所述,这些区域的微观组织特征揭示了焊接接头的不均匀性,其综合机械性能较母材有所下降,焊缝成为接头的最薄弱环节。
[Abstract]:The welding experiment of 7055 aluminum alloy with 2 mm thick spray forming was carried out by laser welding method. The microstructure and mechanical properties of welded joints were analyzed by means of EBSD, SEM, EDS, TEM, microhardness and tensile test at room temperature. The results show that there is no obvious softening in the heat-affected zone of the laser welding joint of W7055 aluminum alloy, and the microhardness of the weld is the lowest, which is about 77% of the base metal. The tensile strength and elongation of the joint are about 61% and 4.1% of the base metal, respectively. The recrystallized equiaxed grains were observed in the heat affected zone, but the dispersed 畏 'phase was observed in the crystal. Near the fusion line, the fine equiaxed non-dendritic zone with random distribution of grain orientation was formed, and the weld zone near the fusion line was columnar dendrite. Near the center of the weld there is cellular dendrite, and there is no dispersive strengthening phase in the crystal. To sum up, the microstructure of these regions reveals the inhomogeneity of welded joints, and the comprehensive mechanical properties of the welded joints are lower than that of the base metal, and the welds become the weakest link of the joints.
【作者单位】：兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室;
【基金】：甘肃省国际科技合作专项(144WCGA164)资助
【分类号】：TG457.14

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