Abstract
Aluminum alloy composites reinforced with short potassium titanate fibers were fabricated by squeeze casting, and the properties at high temperature and turning machinability of the composites were investigated. The composites reinforced with potassium titanate whisker and aluminum borate whisker were also fabricated to compare their properties with the short potassium titanate fiber reinforced composite. The reinforcements were randomly arranged in the alloy matrix, and no agglomeration of the fibers or porosity was observed. The proof strength of the composites were higher than that of the unreinforced alloy. Coefficient of thermal expansion of the composites was smaller than that of the unreinforced alloy. The cutting force was lowered by the reinforcement, and that of the potassium titanate fiber reinforced composite was lower than that of the whisker reinforced composites. The roughness of the machined surface was lowered by the reinforcement. This result and the in-situ observation of cutting process indicate that the reinforcements in the composite suppress the formation of the built-up edge. Continuous chips were formed after cutting the unreinforced alloy, while serrated chips were formed after cutting the composites. Tool wear after cutting has also been investigated.
