母材微量元素对6063铝合金接触反应钎焊的影响

Effect of microelement on contact-reaction brazing of 6063 aluminum alloy

采用铜中间层对6063铝合金进行了接触反应钎焊连接,分析了接头的典型界面结构,着重研究了铝合金母材中微量元素对界面及接头力学性能的影响行为.结果表明,接头界面相主要有Al2Cu,α-Al,Mg2Si,ω-FeCu2Al7.Fe元素导致较高连接温度下ω-FeCu2Al7板条相的生成,影响接头强度.Mg,Si元素以Mg2Si形式富集在钎缝中心,并随保温时间的延长而加剧富集.接头抗剪强度受控于界面产物的种类及形貌、等温凝固的程度.在570℃/60min时接头平均抗剪切强度最高,可达105.3MPa.

The 6063 Al alloy joint using Cu cladding as reaction layer was obtained by contact-reaction brazing method. The typical interfacial structure of the joint was analyzed,and also the effect of microelement on interface structure and joint strength were emphasized. The results show that the brazing interface consists of Al2Cu,α-Al,Mg2Si and ω-Fe1Cu2Al7,the existence of Fe results in formation of ω-Fe1Cu2Al7 lath-shaped phase and weakens the joint shearing strength,and Mg and Si elements enriches in the center of brazing seam as Mg2Si phase and exacerbates with the extension of holding time. The shearing strength of the joint is mainly controlled by the category and feature of interfacial products and the extent of isothermal solidification,and the highest average shearing strength of the joint can reach 105.3 MPa at brazing temperature of 570 ℃ and holding for 60 min.