Microstructure and tensile behavior of high-chromium cast iron/low-carbon steel composite fabricated by accumulative roll-bonding

Abstract

In the present study, a composite material of high chromium cast iron (HCCI) dispersed in low carbon steel (LCS) matrix was fabricated by the technology of accumulative roll-bonding (ARB). The microstructure characteristics were investigated using scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). The tensile behavior and fracture characteristics of the composite were analyzed. The obtained microstructures illustrated that the HCCI was dispersed in the LCS after 3rd ARB cycle, forming a kind of composite material somewhat similar in its structure to a concrete. The coarse Cr-carbides of HCCI were broken and refined obviously through the hot-rolling deformation. However, some microcracks were formed on the fractured Cr-carbides of HCCI. The two materials were bonded by mechanical and metallurgical bonding, and a diffusion band with a thickness of ∼10 µm was formed on the interface. Compared with the as-cast HCCI plate, the composite material after 3rd ARB cycle possessed good comprehensive tensile properties. The fracture characteristics of the composite material included the multiple tunnel fracture of HCCI and the shear fracture of LCS.