In-situ alloying of BNi2+Ni interlayer for brazing C/C composites and GH3536 Ni-based superalloy

Abstract

C/C composites are brazed to GH3536 superalloy with BNi2+Ni interlayer based on in-situ alloying conception. Through the liquid-solid reaction and diffusion, the original microstructure of C/C/Cr23C6/Ni(s,s)+Cr3Ni2+Ni-Si + Cr9Mo21Ni20/GH3536 is transformed into C/C/Cr7C3/Ni(s,s)/GH3536. High Ni (s,s) content increases the deformability and uniforms the composition of joint. Residual stress caused by the property mismatch is modified through deformability increase. Both increases the joining strength consequently. The phase of low melting point diffuses into Ni interlayer, which improves the high temperature performance efficiently. The optimal range of Ni interlayer is from 150 μm to 300 μm. The highest shear strength of joint reaches 32.6 MPa and 20.1 MPa at room temperature and 1000 °C, respectively.