Production of TiB2/B4C hybrid particle reinforced aluminum composites and investigation of their machinability in milling

In this study, aluminum-based composites reinforced with TiB2 and B4C in three different volume ratios were produced by the powder metallurgy method. The total volume ratios of TiB2 and B4C reinforcements, which are used in equal proportions, are 6, 12 and 18%. After weighing the powders on a precision scale, they were mixed for 2 hours in a 3D mixer using 5 mm diameter zirconia balls. Afterward, the cold compression at 400 MPa pressure and then microwave sintering at 620 °C for 45 minutes in an argon gas environment were applied to the samples. After examining the microstructures and measuring the macro hardness of the produced composites, the composites were machined using TiAlN-TiN coated cemented carbide inserts at 0.10 and 0.18 mm/tooth feed and 150, 200 and 250 m/min cutting speeds on a computer numerical control milling machine. The machinability of the composites was investigated by examining the flank wear of the used cutting tips and the surface roughness of the samples. As a result of the study, the highest tool life was observed at 0.18 mm/tooth feed and 150 m/min cutting speed for the 6 vol% reinforced sample, while the lowest surface roughness was observed at 0.10 mm/tooth feed and 250 m/min cutting speed for the 18 vol% reinforced sample. In the composite samples produced, it was determined that the tool life was inversely proportional to the cutting speed and reinforcement ratio, while it was directly proportional to the feed. In addition, the surface roughness decreased as the cutting speed and reinforcement ratio increased, and the surface roughness increased as the feed increased.