Turning Machinability of Short Carbon Fiber Reinforced Aluminum Alloy Composite

Abstract

Turning machinability of aluminum alloy composites reinforced with carbon fibers was examined using a carbide tool. Pitch-based short carbon fiber was used as the reinforcement. The composites were fabricated by squeeze casting. Optical microscopy revealed that the fibers were randomly arranged in the alloy matrix. The fiber reinforcement decreased the hardness of the alloy. The fiber reinforcement also decreased the cutting resistance of the aluminum alloy, and the resistance values of the composite was lower than that of a composite reinforced with short alumina fibers. The roughness of the machined surface was significantly decreased by the fiber reinforcement under every cutting condition. No carbide tool wear was observed even if the composite underwent a machining of 2 km, whereas the tool wear was clearly observed for the alumina fiber-reinforced composite. These results indicated that the carbon fibers in the alloy act as a solid lubricant. Chips formed by machining the composite were powdery, whereas the chips formed by machining the unreinforced aluminum alloy was long.