Machinability of Short Alumina Fiber Reinforced Al-Si-Cu-Ni-Mg Alloy Composite

Abstract

Short alumina fiber-reinforced aluminum alloy composites were fabricated by squeeze casting, and the effects of the fiber reinforcement on the machinability of the alloy under various cutting conditions were investigated. Al-Si-Cu-Ni-Mg alloy (JIS-AC8A alloy) was used as the matrix metal. The mean values of the cutting force of the AC8A alloy were reduced by the fiber reinforcement. The lower the hardness of the fiber in the composite, the lower the cutting force of the composite. The range of the variation in the cutting force during the cutting of the composite reinforced with lower-hardness alumina fibers was almost the same as that of the AC8A alloy. The roughness of the machined surface decreased by the fiber reinforcement under every cutting condition, and the roughness of the composites was almost the same as the theoretical roughness when the cutting speed and feed rate were high. This result indicates that the fibers in the composite suppress the formation of the built-up edge. The machined surfaces and 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. These results lead to the conclusion that the machinability of the composites is superior to that of the AC8A alloy.

Turning Machinability of Short Alumina Fiber Reinforced Aluminum Alloy Composite Using Carbide Tool

“…As with the cutting force, no significant change in the feed force along with the cutting speed was recognized for every specimen. Table 2 shows a comparison of the cutting force and feed force in the present study (tool: carbide) to those in the previous study 8) (tool: diamond (PCD)). It is noted that the cutting and feed forces when the carbide tool is used are greater than that when the diamond tool is used for every specimen.…”

“…7(a) and (b) shows that the values increased as the feed rate increased for every specimen. The theoretical roughness values, which can be geometrically calculated from the nose radius of the cutting tool and feed rate, 8) are also shown in Fig. 7 (R th , dotted line).…”

“…The chemical composition, properties and SEM micrographs of the fibers are described in a previous report. 8) Although the average fiber diameter of these alumina fibers is almost the same (4 µm), the hardness of the fibers are different due to the difference in the chemical and mineral compositions. The hardness of the fibers A and B is 1500 HV and 2000 HV, respectively.…”

“…In a previous report, our research group fabricated an alumina fiber-reinforced aluminum alloy composite, then clarified that the cutting resistance and machined surface roughness in turning operations decreased due to the fiber reinforcement. 8) In the previous study, a diamond tool was used. A diamond tool is usually used for machining the aluminum alloy because the diamond tool has a significant effect on preventing the machined material from smearing on the tool.…”

Turning Machinability of Short Carbon Fiber Reinforced Aluminum Alloy Composite

“…In a previous report, the author fabricated alumina ber-reinforced aluminum alloy composites, then clari ed that the cutting resistance during turning operations and machined surface roughness decreased due to the ber reinforcement 8,9) . The replacement of the hard alumina ber with the carbon ber would decrease the cutting resistance, roughness, and tool wear due to its self-lubricant properties.…”