Interfacial design and strengthening mechanisms of AZ91 alloy reinforced with in-situ reduced graphene oxide

This work highlights to develop an in-situ process to disperse uniformly graphene possessing good interfacial bonds with the matrix of Mg alloy. A homogeneous distribution of graphene in the matrix has been successfully obtained through in-situ reduction of graphene oxide (RGO) by sintering process after the graphene oxide (GO) was uniformly dispersed in AZ91 powders. The interface product nano-sized MgO can significantly improve the interfacial bonding strength between RGO and alpha-Mg with analysis by transmission electron microscopy. The orientation relationships of ((2) over bar 00)(Mgo)//((1) over bar 10 (2) over bar)(alpha-Mg) and [011](MgO)//[2 (4) over bar2 (3) over bar](alpha-Mg) with the semi-coherent interface characteristics were clarified for the first time at the interface of MgO/alpha-Mg, suggesting a good lattice space matching. By employing such process, a composite containing 0.5 wt% of GO shows an 85.7% and 61.4% increase in yield strength and elongation, respectively, over unreinforced AZ91 alloy. The underlying strengthening mechanisms of in-situ reduced graphene oxide are discussed in detail.