Fractography, fluidity, and tensile properties of aluminum hematite particulate composites

This paper examines the effect of hematite (iron oxide) particles on the fl uidity of the molten composite as well as the tensile properties and fractu re behavior of the solidified as-cast aluminum composites. The percentage o f hematite in the composite was varied from 1 to 7% in steps of 2% by weigh t. The vortex method was employed to prepare the composites. It followed fr om the results obtained that the ultimate tensile strength and Young's modu lus of the composite increased while the liquid fluidity and solid ductilit y decreased with the increase in hematite content in the composite specimen s. The fluidity of the liquid was greater in a metal mold than in a sand mo ld, and it decreased with an increase in reinforcing particle size and incr eased with pouring temperature. The presence of the reinforcing particles a ltered the fracture behavior of the solid composites considerably. Final fr acture of the composite occurred due to the propagation of cracks through t he matrix between the reinforcing particles.