Structure, chemical stability and properties of NiAl-Al2O3 interface modified by hBN and MAX-phase interlayers

The interlayers from different materials were used in order to modify the interface structure/property and to improve the mechanical properties of NiAl composites reinforced by continuous single crystal Al2O3 fibers. It was found that the interface without interlayer had a good chemical stability during hot pressing (sample fabricating), resulting in high interface shear strength (about 250 MPa) at RT. But for the composites with interlayers, chemical reactions occurred in the interfacial area during diffusion bonding. The measured interface shear strength for the complete debonding was 70±30 MPa, 110±36 MPa and 32±5 MPa for the composites with hBN, Cr2AlC and V2AlC interlayers respectively. The possible influences by introducing the interlayers on mechanical performance of NiAl composites are discussed.