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In order to relieve high residual stresses between ceramics and metals during brazing processes, an AgCuTi/graphene-reinforced Cu foam composite filler was developed and used to braze the ZrB 2 -SiC ceramic and Inconel 600 alloy. Microstructures and shear strengths of the joints were systematically studied. The joints are composed of TiFe 2 , TiCu, TiC, Cu(s, s), Ag(s, s), and Ti 5 Si 3 phases. It is found the addition of graphene on the Cu foam surface can effectively retard diffusions of metal atoms and avoid the collapse of the foam matrix. After being brazed at 900 °C, the joint can get a maximum shear strength of 157 MPa, much higher than those brazed without graphene addition. The high shear strength was investigated in detail and attributed to the integrity of the Cu foam, formation of the TiC and thickness of the reaction layer at the ceramic side. [ABSTRACT FROM AUTHOR]

Abstract In this paper, brazing behaviors between ZrB 2 SiC and Ti 6Al 4V by Cu foam interlayer were studied. The microstructure, formation mechanism, mechanical property and fracture surface of the joints were systematically studied. The results showed that the phases in the joints were α + β -Ti, TiCu, Ti 2 Cu, Cu(s, s), TiC, TiB 2 and Ti 3 SiC 2. An optimum shear strength reached up to 435 MPa at a brazing temperature of 910 °C and holding time of 20 min. Such a shear strength was 90 MPa higher than the one without the Cu foam. The obtained high shear strength of joint was discussed from microstructure and residual stress. With the increase of brazing time, Cu(s,s) gradually disappeared and the content of Ti 2 Cu intermetallic compound increased, which was harmful for the joint. Furthermore, the residual stress of joint with Cu foam was calculated to be 324 MPa, lower than the one without Cu foam interlayer. [ABSTRACT FROM AUTHOR]