Microstructural and mechanical characterisation of a second generation hybrid metal extrusion & bonding aluminium-steel butt joint
Microstructural and mechanical characterisation of a second generation hybrid metal extrusion & bonding aluminium-steel butt joint
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DOI：
10.1016/j.matchar.2020.110761
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发表时间：
2021-03-02
影响因子：
4.7
通讯作者：
Vullum, Per Erik
中科院分区：
文献类型：
--
作者：
Bergh, Tina;Sandnes, Lise;Vullum, Per Erik
混合金属挤压和粘合（HYB）是一种连接方法，通过连续挤压和旋转钢工具施加的压力结合添加铝填充材料，实现固态粘合。本文介绍了铝合金6082和结构钢5355的第二代HYB对接接头的力学和显微组织特征。抗拉强度为184 ~ 220 MPa，节理效率为60 ~ 72%。拉伸试验过程中应变发展的数字图像相关分析显示，在最终断裂靠近铝-钢界面之前，已经形成了根裂纹。在钢断口上发现了大量的残余铝，特别是在连接过程中承受较高压力的区域。扫描电镜和透射电镜分析表明，结合强度可归因于微尺度的机械联锁和不连续的纳米尺度Al-Fe-Si界面金属间相层的结合。对倾斜系列扫描电子衍射数据的分析表明，多晶金属间相层含有立方α (c)相。研究结果揭示了铝-钢连接的结合机理和HYB连接的性能，为进一步理解和发展铝-钢连接工艺提供了理论依据。
Hybrid metal extrusion & bonding (HYB) is a joining method that enables solid-state bonding by combining addition of aluminium filler material through continuous extrusion with pressure exerted by a rotating steel tool. This work presents mechanical and microstructural characterisation of a second generation HYB butt joint of aluminium alloy 6082 and structural steel 5355. The ultimate tensile strength was measured to be in the range of 184-220 MPa, which corresponds to 60-72% joint efficiency. Digital image correlation analysis of the strain development during tensile testing revealed that root cracks formed, before the final fracture ran close to the aluminium-steel interface. A significant amount of residual aluminium was found on the steel fracture surface, especially in regions that experienced higher pressure during joining. Scanning and transmission electron microscopy revealed that the bond strength could be attributed to a combination of microscale mechanical interlocking and a discontinuous nanoscale interfacial Al-Fe-Si intermetallic phase layer. Analysis of scanning electron diffraction data acquired in a tilt series, indicated that the polycrystalline intermetallic phase layer contained the cubic alpha(c) phase. The results give insight into the bonding mechanisms of aluminium-steel joints and into the performance of HYB joints, which may be used to better understand and further develop aluminium-steel joining processes.