6A02铝合金接触反应钎焊接头组织及抗剪强度

Microstructure and shear strength of vacuum contact reactive brazed joints of 6A02 aluminum alloy

  • 摘要: 使用T2铜箔作为中间层,采用真空接触反应钎焊方法进行6A02铝合金的连接试验。采用扫描电镜分析、能谱分析和强度分析等方法,分析了钎焊工艺参数对接头组织和力学性能的影响。结果表明,采用铜箔真空接触反应钎焊6A02铝合金时,钎焊接头两侧易出现溶蚀缺陷,且连接温度越高、保温时间越长,溶蚀的程度越严重,钎缝中没有发现钎焊时常见的气孔、夹渣等缺陷,采用接触反应钎焊可以得到致密的钎焊接头。当连接温度为560 ℃时,钎焊接头组织为6A02合金、α-Al固溶体、CuAl2和Mg2Si;当连接温度为570 ℃,580 ℃时,钎缝中出现短杆状的ω-FeCu2Al7组织,接头组织为6A02合金、α-Al固溶体、CuAl2,Mg2Si和 ω-FeCu2Al7;当连接温度为570 ℃、保温时间为30 min时,获得的接头抗剪强度最高为38.5 MPa,且接头断裂位于6A02钎缝中脆性的CuAl2化合物反应层。

     

    Abstract: Vacuum contact reactive brazing was used to carry out connection test of 6A02 aluminum alloy with T2 copper foil as interlayer. Analysis method of SEM, energy spectrum and strength were adopted to analyze influence of brazing parameters on microstructure and mechanical properties of brazed joints. The results showed that when copper foil vacuum contact reactive brazing of 6A02 aluminum alloy was used, corrosion defects were easy to appear on both sides of brazed joints. Moreover, the higher connection temperature was and the longer holding time was, the more serious dissolution degree was. Common defects such as porosity and slag inclusion were not found in brazed joints, and dense brazed joints could be obtained by contact reactive brazing. When joining temperature was 560 ℃, microstructure of brazed joints consisted of 6A02 aluminum alloy, α-Al solid solution, CuAl2 and Mg2Si. When joining temperature was 570 ℃ and 580 ℃, short rod-shaped ω-FeCu2Al7 microstructure appeared in brazed joints, and microstructure appeared in brazed joints was 6A02 alloy, α-Al solid solution, CuAl2, Mg2Si and ω-FeCu2Al7. When joining temperature 570 ℃ and holding time was 30 min, the maximum shear strength of brazed joints was 38.5 MPa, and fracture was located in the brittle CuAl2 reaction layer of 6A02 brazing seam.

     

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