Relationship between interfacial reaction and mechanical properties of Al_(18)B_4O_(33) whisker reinforced Mg, Al alloy composites

摘要

Al_(18)B_4O_(33) whisker reinforced Al, Mg alloy composites prepared by squeeze casting process reacts at the interface between whisker and matrix by heat-treatment after fabrication. This interfacial reaction affects its mechanical properties. The interfacial reaction causes the degradation of bending strength of the composites. In pure Al matrix composite, the interfacal reaction occurred only at a temperature higher than above 750 C and its reaction products are γ-Al_2O_3. Interfaces between whisker and the reaction products have preferred orientations with little mismatch. In AC8A matrix composite, the degradation of the bending strength is observed at a temperature higher than 500 C. The reaction products are MgAl_2O_4 and it forms like trapezoid. On the other hand, in AZ91D matrix composites, reaction products are MgAl_2O_4 layer with a uniform thickness. This layer prevents the direct reaction between whisker and matrix.