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钎焊温度及保温时间对Sn-30Zn钎料钎焊Mg/Al异种金属组织和性能的影响

Effect of brazing temperature and holding time on microstructure and strength of brazed joints between dissimilar materials Mg/Al

  • 摘要: 采用Sn-30Zn(质量分数,%)钎料对Mg/Al异种金属进行低温钎焊.并利用扫描电子显微镜、电子探针研究了钎焊接头在不同焊接工艺参数下的微观组织演变过程,同时采用维氏硬度仪及万能力学性能试验机对接头的显微硬度和力学性能进行了测试.结果表明,当钎焊温度为330℃,保温时间为5 s时,钎焊接头组织性能较好.接头组织主要分为近镁侧的Mg2Sn化合物层、近铝侧的Al-Sn-Zn固溶体层、焊缝中心三个区.焊缝中心区以Sn-Zn的过共晶组织为基底,上面弥散分布着Mg2Sn相,铝基固溶体相.接头的最佳平均剪切强度为60.47 MPa.

     

    Abstract: In the present work, low temperature brazing of Mg/Al dissimilar metal with Sn-30Zn solder is successfully realized.Microstructure of the brazed joints is analyzed by scanning electron microscopy(SEM) and electronic probe micro-analyzer(EPMA).Microhardness and shear strengh of the joints are also investigated by Vickers hardness tester and universal material machine, respectively.The result shows that excellent microstructure and mechanical properties will be obtianed while the brazing temperature is 330℃ and holding time is 5 s.The microstructure of joint consists of a multilayer sandwich structure which comprise transition zone of Mg2Sn near the Mg base metal, transition zone of Al-Sn-Zn solid solution near the Al base metal, and the central zone between them.The Mg2Sn and Al-Sn-Zn solid solution phases are dispersed in Sn-Zn hypereutectic structure at this zone.With these brazing prameters, the average shear strength of the brazed joints is 60.47 MPa.

     

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