Microstructure and mechanical properties of SiCf/SiC composites/ GH536 superalloy joints brazed with CoFeNiCrCu high-entropy alloy filler

Abstract

Brazing is a crucial technology to achieve the connect of the stator blades of aero-engine and the inner and outer rings of casing. In this work, SiC f /SiC and GH536 were brazed by using a high entropy alloy CoFeNiCrCu filler. The interfacial microstructure, brazing mechanism and mechanical properties of the joint were investigated by SEM, TEM and shear strength test. The interfacial reaction was dominated by reactive elements in the initial stage of brazing. The phase structure of the interlayer did not change due to the high entropy mixing effect of the filler. Thus, the typical microstructure of CMCs/Cr 23 C 6 /Ni 2 Si/FeSi/MoNiSi/Cr 4 Fe 4 NiC 4 /FCC/Ni(s,s)/GH536 could be identified at welded joint. Owing to high entropy effect of CoFeCrNiCu filler, random solid solution turned out in the seam, thus the mechanical properties of the joint were greatly enhanced. This work offers a new idea and technological paradigm to develop the aero-engine manufacturing industry for engineers and researchers. • SiC f /SiC composite and GH536 were brazed by CoFeNiCrCu filler successfully. • The maximum shear strength of brazed joint was up to 86 MPa. • A physical model was proposed to describe the microstructure evolution.