Joining of a Si-Ti-C-O Fiber-Bonded Ceramic and an Fe-Cr-Ni Stainless Steel with a Ag-Cu-Ti Brazing Alloy

Abstract

Joining of a Si-Ti-C-O fiber-bonded ceramic and an Fe-Cr-Ni stainless steel with a Ag-Cu-Ti brazing alloy was carried out. For relaxation of thermal stress caused by thermal expansion mismatch between the ceramic and the stainless steel, a thin pure copper plate was set between the specimens to be joined. Joining strength was evaluated by a four-point bending test at room temperature. The highest strength of ceramic/stainless steel joint attained in this study was 230MPa. The scattering of the strength was narrow. The ceramic-side fracture surfaces of the joints were divided into many regions by fiber/matrix interfacial cracks. It was inferred that those fiber/matrix interfacial cracks, which were perpendicular to the main crack along the joining interface, decreased the stress intensity factor of the main crack and increased the strength of the joint.