Turning machinability of short alumina fiber reinforced aluminum alloy composites

Fiber-reinforced aluminum alloy composites were fabricated by squeeze casting, and the effects of the fiber reinforcement on the machinability of the alloy were investigated. Al-Si-Cu-Ni-Mg alloy was used as the matrix metal, and two kinds of short alumina fibers were used as the reinforcements. The cutting force values of the alloy were reduced by the fiber reinforcement under every cutting condition. The lower the hardness of the fiber in the composite was, the lower the cutting force of the composite was. The roughness of the machined surface decreased by the fiber reinforcement. This result and the in situ observation of cutting process revealed that the fibers in the composite suppress the formation of the built-up edge. The observation of chip forms indicated that the fibers in the composite facilitated the shear deformation of the chips because the fibers were easily sheared by the cutting. Continuous chips were formed after cutting the unreinforced alloy, while serrated chips were formed after cutting the composites. The lower the hardness of the fiber in the composite was, the lower the tool wear was.