Interfacial microstructure and strengthening mechanisms of Cf/Mg composite with double-layer interface

Abstract In order to overcome the interfacial incompatibility of carbon fiber reinforced magnesium matrix (Cf/Mg) composites, a double-layer interface (ZrO2–MgO) is designed in this work. Carbon fiber was modified with ZrO2 coating by sol-gel process. Microstructural examination reveals that MgO layer forms on the surface of ZrO2 coating by ZrO2 reacting with Mg during the composite fabrication. Such double-layer interface could inhibit Al4C3 and hence prevent fiber damage. Meanwhile, the wettability was improved for the reaction between ZrO2 and Mg. Thus the tensile strength of ZrO2-Cf/AZ91D composite was 68.0% higher than that of the unmodified one. Due to the fiber bundle pull-out, debonding and crack deflection, the toughness of Cf/Mg composite with double-layer interface is increased simultaneously.