Microstrucmre and fracture behavior of SiO2 glass ceramic and TC4 alloy joint brazed with TiZrNiCu alloy

摘要

Vacuum brazing of SiO2 glass ceramic and TC4 alloy using a commercially available TiZrNiCu foil was investigated. The interfacial microstructure and the fractures were examined with an optical microscope(OM) and an S-4700 scanning electron microscope(SEM) equipped with an energy dispersive spectrometer(EDS) and an electron probe X-ray microanalyzer(EPMA) . The structure of joint interface was identified by XRD(JDX-3530M) . Meanwhile,the fracture paths of the joints were comprehensively studied. The results show that processing parameters,especially the brazing temperature,have a significant effect on the microstructure and mechanical properties of joints. The typical interface structure is SiO2/Ti2O+Zr3Si2+Ti5Si3/(Ti,Zr) +Ti2O+ TiZrNiCu/Ti(s.s) /TiZrNiCu+Ti(s.s) +Ti2(Cu,Ni) /TC4 from SiO2 glass ceramic to TC4 alloy side. Based on the mechanical property tests,the joints brazed at 880 ℃ for 5 min has the maximum shear strength of 23 MPa.