| 摘要: |
| 本文旨在通过改善焊接工艺,提高铝-钛接头性能,扩大铝-钛复合件的应用范围。通过在铝-钛熔钎焊接工艺中添加锌箔,探讨了中间层锌箔对铝-钛接头微观组织和力学性能的影响。采用TIG焊机对铝/钛异种金属板材进行熔钎焊接实验,利用金相显微镜、扫描电镜、能谱仪、维氏硬度计和电子拉伸机对铝/钛接头的微观组织和机械性能进行分析。研究发现,添加锌箔可以明显改善液态铝合金在钛合金表面的润湿性。当焊接电流偏低时,可以观察到熔焊区存在弥散分布的锌元素,钎焊区有锌颗粒夹杂；焊接电流为90 A时,熔焊区和钎焊区分别有棒状和连续的TiAl3金属间化合物生成；继续增大电流,TiAl3相的数量急剧增加并伴随裂纹出现。硬度检测结果表明,在焊缝垂直方向上,钎焊区的硬度值最高达到了173HV,远高于熔焊区。钎焊区硬度值的升高,主要是由于该区域有脆硬的Ti-Al金属间化合物生成。拉伸实验结果表明,焊接电流为90 A时,铝/钛接头的抗拉强度达到最大,为227 MPa。热输入的增加使钎焊区发生了充分的冶金结合,断裂最终发生在接头熔焊区。在铝/钛熔钎焊过程中添加金属锌箔,有利于改善接头成形,提高铝-钛接头焊接质量。 |
| 关键词: 金属材料的焊接 铝合金 钛合金 微观组织 力学性能 |
| DOI：10.11951/j.issn.1005-0299.20210208 |
| 分类号:TG457.1 |
| 文献标识码:A |
| 基金项目:重庆市教委科学技术研究项目(KJQN201904001). |
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| Effect of intermediate zinc foil on microstructure and mechanical properties of Al-Ti dissimilar joints |
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WANG Dapeng, LI Xiaofeng
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(College of Intelligent Manufacturing and Automobile, Chongqing Technology and Business Institute, Chongqing 401520, China)
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| Abstract: |
| This paper aims to improve the properties of Al-Ti joints and expand the application range of Al-Ti composite parts by improving the welding process. The influence of intermediate zinc foil on the microstructure and mechanical properties of Al-Ti joints was investigated by adding zinc foil to the Al-Ti brazing-fusion welding process. A TIG welding machine was used to conduct welding and brazing experiments on Al/Ti dissimilar metal sheets. The microstructure and mechanical properties of Al/Ti joints were analyzed by means of metallographic microscope, scanning electron microscope, energy spectrometer, Vickers hardness tester, and electronic tensile machine. Results show that the wettability of liquid Al alloy on Ti alloy surface could be improved by adding zinc foil. When the welding current was low, dispersed zinc elements could be observed in the fusion zone, and there were zinc particles in the brazing zone. When the welding current was 90 A, rod-like and continuous TiAl3 intermetallic compounds were formed in fusion zone and brazing zone respectively. However, as the current continued to increase, the number of TiAl3 phases increased sharply and cracks appeared. Hardness test results show that in the vertical direction of the weld, the hardness value in the brazing zone reached up to 173HV, which was much higher than that in the fusion zone. The increase in the hardness value in brazing zone was mainly due to the formation of brittle and hard Ti-Al intermetallic compounds in this region. Tensile test results show that the maximum tensile strength of Al/Ti joint was 227 MPa under the welding current of 90 A. The increase in heat input led to sufficient metallurgical bonding in the brazing zone, and the fracture finally occurred in the fusion zone of the joint. The above experimental results indicate that the addition of metal zinc foil in the process of Al/Ti fusion brazing is conducive to improving joint forming and welding quality. |
| Key words: welding of metal materials aluminum alloy titanium alloy microstructure mechanical property |
