Microstructure and joining strength evaluation of SiC/SiC joints brazed with SiCp/Ag–Cu–Ti hybrid tapes

Author： Liu Yan Qi Qian Zhu Yunzhou Zhang Jingxian

E-ISSN： 1568-5616|29|15|1563-1571

ISSN： 1568-5616

Source： Journal of Adhesion Science and Technology, Vol.29, Iss.15, 2015-08, pp. : 1563-1571

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Abstract

SiC particulates were mixed with Ag–Cu–Ti powders to fabricate SiC_P/Ag–Cu–Ti (SICACT) sheets by tape casting process, which were used to braze the sintered SiC ceramics with the structure of SiC/Ag–Cu–Ti foil/SICACT sheet/Ag–Cu–Ti foil/SiC. Microstructure and joining strength both at room temperature and at high temperature were characterized by electron probe X-ray microanalyzer, electron dispersive spectroscopy, transmission electron microscopy, and flexural strength test. The SiC particulates from the SICACT sheets were randomly distributed in the filler alloy matrix and reacted with Ti from the filler alloy. Reaction products TiC and Ti₅Si₃ were found in the interfacial reaction layer. With the increase in SiC particulates volume fraction, the joining strength at room temperature first increased, and then decreased, which was affected by both CTE mismatch and the thickness of the reaction layer. In addition, the joining strength of joints brazed using SICACT sheets at 600 °C can reach 197 MPa, which was obviously higher than that brazed using Ag–Cu–Ti filler alloy.