Abstract
In this study, interfacial characteristics in bimetal composites composed of (i) grey cast iron (GCI) as a brittle matrix and (ii) stainless steel (SAE310) and steel wires (AISI1020) as ductile reinforcements were investigated. Flexural behavior of GCI and bimetal composite beams was examined under three-point bending test. Current results revealed that carbon and alloying elements diffused from the molten iron to the ductile reinforcement across the interface enhancing the metallurgical bond across the interface of produced composite beams. The diffusion of carbon from GCI into SAE310 side resulted in the formation of chromium carbides in that side near the interface. Chromium diffused from SAE310 into GCI led to the formation of M7C3 eutectic carbides in GCI near the interface. As a consequence, the ductile reinforcement may lose some of its ductility and behaves as a brittle material especially at the region near the interface. Microhardness and microstructure variations across the interface are related to the diffusion of carbon and alloying elements. The introducing of steel wires with a lower area ratio (i.e. 2.2%) into the GCI matrix bimetal composite did not reveal any obvious developments in changing failure mode of this material. Inserting SAE310 plates into composite beams resulted in a noticeable improvement in their mechanical properties as compared with GCI beam without reinforcement. Specimens of the bimetal composites with SAE310 plates failed in a ductile mode with slight plastic deformation before failure. This may be due to lower volume fraction of SAE310 plates.