An Al–7Si alloy/cast iron bimetallic composite with super-high shear strength

Publication date: Available online 28 May 2019Source: Journal of Materials Research and TechnologyAuthor(s): Zhilin Guo, Min Liu, Xiufang Bian, Meijia Liu, Jianguo LiAbstractA new composite technology is presented consisting of the surface pretreatment of cast irons, the hot-dipping in a Zn–0.2 wt.% Bi melt and the Al/Fe composite process. The shear strength of Al/Fe (Al–7Si/cast iron) bimetallic composites fabricated by the technology is up to 32 MPa that is far more than the shear property obtained by composite technology reported in literatures. The super-high shear strength is mainly attributed to the formation of a peculiar concave–convex interface (CCI) structure. The addition of 0.2 wt.% bismuth into the zinc melt can promote the formation of Zn-rich regions at the surface layer of cast irons, leading to the formation of Al–Fe phases at these Zn-rich regions. Reducing the amount of Al–Fe phases appearing in the ferrite–graphite interface in cast irons can benefit improving the shear property of Al/Fe bonding interface. Further analysis of the stress state confirms that the CCI can enhance the shear strength of Al/Fe bonding interface.

Source: Journal of Materials Research and Technology - May 29, 2019 Category: Materials Science Source Type: research