Preparation and mechanical performance of graphene platelet reinforced titanium nanocomposites for high temperature applications

Abstract

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

“…Introducing the GNPs in brazing is the important strengthening factor. 41 It did strengthen the filler matrix by refining the matrix microstructure and hindering the dislocation slip, whereas high density dislocation morphology caused by reinforcing particles induced the dislocation pile-ups within the matrix, as shown in Figure 6. 41 Meanwhile, in-situ TiC P can also provide additional inhibition of the grain growth.…”

“…What should be noted is TiC P are the hard intermetallic phase which can hardly deform. 41 It did strengthen the filler matrix by refining the matrix microstructure and hindering the dislocation slip, whereas high density dislocation morphology caused by reinforcing particles induced the dislocation pile-ups within the matrix, as shown in Figure 6. The plastic deformation in the matrix around TiC P was restricted, so a high stress concentration was kept after brazing.…”

“…41 Meanwhile, in-situ TiC P can also provide additional inhibition of the grain growth. Introducing the GNPs in brazing is the important strengthening factor.…”

“…It is worth noting that the lattice fringe with a interlayer spacing of about 0.34 nm, matching the graphite lattice, 39,40 was obtained adjacent to TiC phase. The Gibbs free energy (ΔG 0 ) value for the reaction equation of Ti + C → TiC at 860°C was negative, 41 thereby demonstrating that the reaction was thermodynamically feasible. It was evident that when a carbon source (GNPs) was introduced in the brazing filler metal matrix; TiC P would be produced by the in-situ reaction of carbon materials and Ti atom, as a replacement for the GNPs.…”

“…GNPs with extraordinarily high Young's modulus could improve the strength considerably by its refining effect on the microstructure. 41 Meanwhile, in-situ TiC P can also provide additional inhibition of the grain growth. The uniform distribution of TiC P in the brazing seam would benefit the refinent of the microstructure.…”