The joining of dissimilar materials, such as ceramics and metals, is of significant importance in industries such as aerospace and automotive as this could increase the operating conditions of components. The challenge posed by such ceramic-metal joints is the mismatch in coefficient of thermal expansion that in turn creates thermally induced residual stress. This paper shares findings from a study that investigated effects of joint design and use of interlayers to alleviate the residual stress between ceramic-metal joints. The base materials were alumina, silicon nitride and titanium and joints were formed using Ticusil active braze. The ceramic and metallic specimens were fabricated in accordance with ASTM F19. The ceramic-metal joints were formed in a vacuum furnace and were tested in accordance with ASTM F19. It was found that by reducing the contact area, through the use of knife edges, improvements in joint strength can be realised. Various knife edge geometries were tested and the best performing knife edge resulted in an improvement in average tensile strength of 441 when compared with full face joint of ASTM F19 specimen. The introduction of the interlayer resulted in an average increase of 2935.
展开▼
