The effects of Mg contents on microstructure and tensile properties of Al18B4O33w/Al-Mg composites

Abstract

Al18B4O33 whiskers reinforced Al-Mg matrix composites with different Mg contents are fabricated by squeeze casting method. The effects of Mg contents on the microstructure and the tensile properties of the composites are investigated. The results indicate that the Mg contents have strong influences on the type of interphase, the thickness of interfacial layer and the solid solubility of Mg along with the dislocation density in the matrices of the composites. The interface reaction products between the whiskers and Mg evolve from MgAl2O4 to MgAl2O4+MgO to MgO with the increase in Mg contents. The ultimate tensile strength (UTS) of the composites increases dramatically with the Mg contents, resulting from the combination of the interface strengthening and the solid solution strengthening of Mg. It is worth mentioning that the UTS of the composite containing 10 wt% Mg in the matrix attains a highest value (540 MPa) in as-cast Al18B4O33w/Al composites reported.