【作者】 董健；

【导师】 薛松柏；

【作者基本信息】 机械科学研究院 ， 材料加工工程， 2003， 硕士

【摘要】 本文采用中温钎焊技术，利用改进型CsF-AlF₃无腐蚀性钎剂配合Ag-Al-X-Y钎料、Al-Si-Y（1）钎料和Al-Si-Y（2）钎料实现了对LY12铝合金的中温钎焊连接。避免了LY12铝合金在钎焊过程中容易产生的母材易过烧、钎缝腐蚀等缺陷。 在实现了对LY12铝合金中温钎焊连接的基础上，通过对LY12铝合金中温钎焊工艺参数的研究，发现搭接面积为60～70mm₂，采用496～503℃加热保温15min，并采用随炉冷至450℃后空冷的冷却办法，接头的力学性能最佳，满足钎缝的力学性能的要求。 改进型CsF-AlF₃无腐蚀性钎剂能很好的去除LY12铝合金表面氧化膜，是实现LY12铝合金中温钎焊连接的技术关键。通过对改进型CsF-AlF₃无腐蚀性钎剂去除LY12铝合金表面的氧化膜机制的研究，发现了CsF是去膜关键化合物，提出改进型CsF-AlF₃无腐蚀性钎剂具有高活性的原因与．NH₄F、NH₄AlF₄及复合盐熔体等化合物的存在有关，它们的存在可提高改进型CsF-AlF₃钎剂的去膜能力，而HF的生成则是诱发和加速反应、提高溶解去膜能力的关键。 结合中温钎焊技术在Al／Cu管上的应用和改进型CsF-AlF₃无腐蚀性钎剂自身的特点，提出了CsF-AlF₃无腐蚀性钎剂在其它行业同样具有很大的利用价值，应用前景十分广阔。 综合本文的全部研究工作，发现Al及Al合金的中温钎焊技术具有广阔的应用前景。更多还原

【Abstract】 The technology for brazing LY12 aluminum alloy at middle-range temperature by means of the improved CsF-AlF3 non-corrosive flux matching Ag-Al-X-Y, Al-Si-Y(l) and Al-Si-Y(2) filler metal is presented in this thesis. The defects including the over-heated structure of base metal and the lower corrosion resistance of brazed seam, which usually take place during brazing process, could be eliminated completely.After the sound brazed joint of LY12 alloy at middle-range temperature is obtained, further detailed analysis of the brazing parameters reveals that the optimized joint can be produced at the brazing temperature 496~503℃, dwell time 15min and the lap area 60~70 mm 2 following with cooling to 450℃ in the furnace and then to room temperature in air. The brazed joint meets the need of the required mechanical properties.It is the core point to accomplish the brazing LY12 alloy well at middle-range temperature that the improved CsF-AIFs non-corrosive flux can remove easily the complicated oxide film on the surface of LY12 aluminum alloy. From the research on the mechanism of the improved brazing flux CsF-AlF3 removing the oxide film of LY12 alloy, it is found that the compound CsF plays a key role in removing the oxide film. The high activation of the brazing flux is related to the presence of compound NR^F, NH4A1F4 as well as other melted salts. That is, the ability to remove the oxide film by theflux can be enhanced owing to the impacts of above compounds. In addition, the formation of HF is the key cause to the initiation and acceleration of the reaction and heightens the ability to remove oxide film by dissolving.Through the application of brazing technique at middle-range temperature in Al/Cu tube and the characteristics of the improved CsF-AlF3 brazing flux it could be formulated that the improved brazing flux CsF-AlF3 will possess potential utilization and broad prospects in other fields.Based on the research in this thesis, it could be confident to say that the brazing technique of aluminum and its alloys at middle-range temperature is about to have better application.更多还原