石英纤维复合材料与因瓦合金的胶接辅助钎焊连接分析

Active cement added brazing of quartz fibers reinforced silica composites to Invar alloy

通过表面涂覆活性胶改性的方法,实现了石英纤维复合材料与因瓦合金的胶接辅助钎焊连接.结果表明,含有钛的液态活性胶在焊接加热过程中与石英纤维复合材料表面纤维发生反应,并通过Ag-Cu共晶钎料层、铜中间层与因瓦合金获得致密连接,接头产生TiO,TiC,CuTi,Fe2Ti等化合物,其结构可表示为QFSC/TiO+Si+TiC+Cu(s,s)/CuTi+Cu(s,s)+Ag(s,s)/Cu(s,s)+Ag(s,s)+Fe2Ti/Invar.由不同钎焊温度接头的剪切性能对比试验得出,在850℃保温15min时的接头抗剪强度达到最大值44MPa.表面涂覆活性胶对钎料润湿的促进作用、活性金属元素Ti与复合材料纤维的化学反应及接头焊缝区产生的化合物生成相是影响连接性能的主要因素.

Quartz fibers reinforced silica composites (QFSC) was bonded with Invar alloy effectively through one kind of active cement added brazing process. The results show that the active cement composing of TiH2 reinforces the wettability of QFSC through reaction,and the bonding is formed by interface diffusion and reaction of Ti,Ag-Cu eutectic,pure Cu and matrix materials in brazing. There are seven reaction products generated in the joint QFSC/Invar brazed,namely as TiO,TiC,CuTi,Fe2Ti,Si,Ag (s,s) and Cu (s,s). The interfacial structure of QFSC/Invar joint can be described as QFSC/TiO+Si+TiC+Cu (s,s)/CuTi+Cu (s,s)+Ag (s,s)/Cu (s,s)+Ag (s,s)+Fe2Ti/Invar. The maximum shear strength is 44 MPa for the QFSC/Invar joint brazed at 850 ℃ for 15 minutes. The pre-coating of active cement at the surface of QFSC,and the reactions between Ti,quartz fibers and filler metals are the key factors for effective bonding.