Joining of Ni-TiC FGM and Ni-Al Intermetallics by Centrifugal Combustion Synthesis

Abstract

A centrifugal combustion synthesis (CCS) process has been investigated to join a Ni‐Al intermetallic compound and a Ni‐TiC cermet. The cermet, a tubular graphite mold, and a green compact of reactants consisting of Al, Ni and NiO were set in a centrifugal caster. When the combustion synthesis reaction was induced in the centrifugal force field, a synthesized molten Ni‐Al alloy flowed into the graphite mold and joined to the cermet. The soundness of the joint interface depended on the volume percentage of TiC phase in the cermet. A lot of defects were formed near the interface between the Ni‐TiC cermet and the cast Ni‐Al alloy when the volume percentage of TiC was 50% or higher. For this kind of cermet system, using a functionally graded cermet such as Ni‐10 vol.%TiC/Ni‐25 vol.%TiC/Ni‐50 vol.%TiC overcame this difficulty. The four‐point bending strength of the joined specimen consisting of the three‐layered FGM cermet and cast Ni‐29 mol%Al alloy was 1010 MPa which is close to the result for a Ni‐29 mol%Al alloy specimen.