Microstructural Evolution and Mechanical Properties of 2D-SiCf/SiC and Hastelloy N Joints Using 82.5Au-17.5Ni Brazing Filler

In this paper, SiC fiber reinforced SiC composite (SiCf/SiC) is joined to Hastelloy N alloy using 82.5Au-17.5Ni (wt%) foil as brazing filler. The microstructural evolution of the joints is investigated using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), and Raman spectroscopy. The shear strengths of the joints are tested by the mechanical testing machine. The results show the formation of nanocrystalline graphites, Ni2Si layer, and Ni31Si12 phases. With increasing temperature, Ni2Si is transformed gradually into Ni31Si12. The shear strength reaches a maximum value of 24.5 MPa when the joint is brazed at 1 000 degrees C for 30 min.