Experimental study on the cutting responses and surface integrity of side milled in situ TiB 2 /Al composites

Research on the machinability of particle-reinforced Al matrix composites (PRAMCs) is significant to their industrial applications. In the present article, the side milling process of two in situ TiB2/Al composites (in situ 6% TiB2/2024 Al composite and in situ 4% TiB2/7075 Al composite) and the corresponding Al alloys (2024 Al alloy and 7075 Al alloy) were investigated. Cutting responses, including milling force and temperature, were monitored and analyzed. Surface integrity, including roughness, topology, morphology, microstructure, and residual stress of the machined samples, was comprehensively characterized and analyzed. Results showed that, by adjusting the process parameters in appropriate ranges, the milling force and temperature of in situ TiB2/Al composites can be controlled at almost the same level of those of conventional Al alloys. Besides, in situ TiB2/Al composites showed better surface finish and larger process window than conventional Al alloys, which can be helpful for the side milling of precision parts, especially for ensuring the high surface quality of the workpiece without special setting of the process parameters. It is worthy to be noticed that side milling can make the TiB2 particles distribute more evenly on the sample surface, which can be beneficial to the comprehensive surface mechanical properties of the in situ TiB2/Al composites.