Interface And Performance Of Magnesium Borate Reinforced Aluminum Matrix Composites With Coated Nano-zriconia

Firstly, ZrO2was coated on the surface of magnesium borate whiskers （MBOw）by improved Sol-gel method, differed by the mass ratio MBOw:ZrO2=30:1,15:1and7.5:1respectively, with the volume fraction of the whiskers was about25%. Then,the aluminum composites reinforced by magnesium borate whiskers（MBOw/ZrO₂/20₂4Al） were fabricated by squeeze casting method, and the matrixwas AA2024Al composites.The microstructure of MBOw/ZrO₂/20₂4Al was observed by opticalmicroscope （OM）, X-ray diffraction（XRD）, scanning electron microscope （SEM）and Transmission electron microscope（TEM）. The status of whiskers coating andthe surface microstructure of MBOwwas studied by XRD、SEM and EDS. Theinterfacial reaction of MBOw/2024Al processed by solution（498℃） was studied byXRD and TEM. The tensile properties of MBOw/2024Al composites were measuredand analyzed and more behaviors were measured. These properties belowinfluenced by aging states was studied. The relationship between the tensileproperties with the interfacial reaction was discussed in detail.The result had shown that interfacial reaction had took place in the process ofsqueeze casting and the product of the reaction included γ-Al2O3. Another productof the interfacial reaction, MgAlO2was found after the MBOw/2024Al compositesprocessed by solution process for two hours.The combined states of interfaces between MBOwwith2024Al compositeswere influenced by the solution. Slight interfacial reaction was observed in the as-cast composites by which the interface was slice and straightly. As the solutiontreatment time advanced, interfacial reaction became more and more obvious andmore products appeared on the interface. In the interfacial reaction process,products transformed from the pin formed to steps formed, then grew up, mergedand disappeared in sequence.The tensile properties of MBOw/ZrO₂/20₂4Al composites were obviouslyinfluenced by the degree of interfacial reaction, including the Young’s modulus,tensile strength, and yield strength. Relative to every properties, there was a kind ofperfect interfacial reaction degree respectively for their own influence mechanism.The tensile strength, yield strength of the MBOw/ZrO₂/20₂4Al composites werealso notable influenced by aging process.