Interfacial microstructure and strengthening mechanism of BN-doped metal brazed Ti/SiO2-BN joints

In‐situ synthesis of TiC nanoparticles during joining of SiC ceramic and GH99 superalloy

“…Moreover, a large number of nanoscale particles formed and evenly distributed in the brazing filler metal according to the higher magnification. 13,37 Also noteworthy is that the continuous TiCuNi 2 brittle intermetallic compound layer (inserted in Figure 3A) disappeared, replaced by that of the small TiCuNi 2 particles (a clearer picture was presented in Figure 8C1) and high proportion of Cu(s,s) (confirmed by Figure 4C). The diffraction peaks of TiC phase were not, however, so obvious because of its small percentage composition and atomic mass; it was speculated that these fine grain particles were TiC phase.…”

“…High CTE mismatch between SiC ceramic (4.7 × 10 −6 /K) 49 and AgCuTi brazing filler metal (18.2 × 10 −6 /K) 13,14 led to a large residual stress in the joints, degrading the mechanical properties of the brazed joint. High CTE mismatch between SiC ceramic (4.7 × 10 −6 /K) 49 and AgCuTi brazing filler metal (18.2 × 10 −6 /K) 13,14 led to a large residual stress in the joints, degrading the mechanical properties of the brazed joint.…”

“…In-situ synthesis TiC P with low CTE (7.4 × 10 −6 / K) 26,49 could reduce the CTE mismatch and thus relieve the residual stress in the joints to a certain extent. [ 13 ]: [ 13 ]:…”

“…[7][8][9][10][11][12] However, a dependable brazed joint depends not only on the strong interfacial bond but on the favorable stress gradient formed in the joint. 13 AgCuTi brazing filler metal can alleviate the residual stress through its good plastic deformation, but it also can induce the large CTE mismatch in the brazing couples due to high CTE (CTE AgCuTi : 18.2 × 10 −6 /K) 13,14 , which is deleterious to the mechanical soundness of the brazed joint.…”

Effect of holding time on microstructure and mechanical properties of SiC/SiC joints brazed by Ag-Cu-Ti + B4C composite filler

“…Unfortunately, directly adding reinforcements has many intrinsic disadvantages, such as heterogeneous distribution and poor wetting ability [21][22]. Hence, in situ synthesized reinforcements were developed with considerable advantages, such as fine size, uniform distribution and favorable cohesion with matrix [23]. Zhu et al [24] reported that, by introducing 12 vol% short carbon fibers into Ag-Cu-Ti filler, TiC particles were formed in the brazing seam and an approximately 30% increase in the shear/tensile strength of the stainless steel/alumina joints was observed.…”