TiC增强C_f/SiC复合材料与钛合金钎焊接头工艺分析

Analysis of brazed joints between carbon fiber reinforced SiC composite and titanium alloy with TiC

采用Ag-Cu-Ti-(Ti+C)混合粉末作钎料,在适当的工艺参数下真空钎焊Cf/SiC复合材料与钛合金,利用SEM,EDS和XRD分析接头微观组织结构,利用剪切试验检测接头力学性能.结果表明,钎焊后钎料中的钛与Cf/SiC复合材料发生反应,接头中主要包括TiC,Ti3SiC2,Ti5Si3,Ag,TiCu,Ti3Cu4和Ti2Cu等反应产物,形成石墨与钛原位合成TiC强化的致密复合连接层.TiC的形成缓解了接头的残余热应力,并且提高了接头的高温性能.接头室温、500℃和800℃高温抗剪强度分别达到145,70,39 MPa,明显高于Cf/SiC/Ag-Cu-Ti/TC4钎焊接头.

Carbon fiber reinforced SiC(Cf/SiC) composite was successfully joined to titanium alloy with Ag-Cu-Ti-(Ti+C) mixed powder under proper parameters.The interfacial microstructure was examined with scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and X-ray diffraction(XRD),and the mechanical properties of the brazed joints were tested.The results showed that Ti in the powder reacted with the composite during brazing,the resultant joints mainly consisted of TiC,Ti3SiC2,Ti5Si3,Ag,TiCu,Ti3Cu4 and Ti2Cu phases.The dense bonding layers formed and were reinforced by TiC in situ synthesized from the reaction between C and Ti in the filler materials.The TiC particulates obviously relieved the thermal stress in the heterogeneous joint,resulting in an increase in shear strength of the brazed joint.The maximum shear strengths of the brazed joints at room temperature,500 ℃ and 800 ℃ reached 145 MPa,70 MPa and 39 MPa,respectively,which were remarkably higher than those brazed with Cf/SiC/Ag-Cu-Ti/TC4.