Basic Research On Machinability Of SiCp/Al Matrix Composites

silicon carbide particle reinforced aluminum matrix composites(SiCp/Al) have many excellent mechanical and physical properties such as improved strength and stiffness, increased corrosion and wear resistance, low density and good dimensional stability over unreinforced alloys. These outstanding properties make SiCp/Al composites increasingly be used in aerospace, precision instruments, electronics and even in ships and bridges, etc. However, this material is hard to machine because of the existence of SiC particles, which can cause problems such as serious tool wear, poor surface quality during its' machining. Both experimental and theoretical analysis of SiCp/Al composites' machinability are performed in this thesis. And cutting force is discussed and studied mainly. All these studies can provide a theoretical and technological base for turning and the actual production of SiCp / Al composites.The main contents and conclusions are as follows:1.The theoretical remove mechanism during turning SiCp/Al composites is studied. Mainly discusses the way aluminum matrix and SiC particles are removed and their influence on surface quality. Chip formation mechanism is also been studied. The deformation behavior of SiC particles has certain influence on the remove of whole material, surface quality and the formation of serrated chips.2.A theoretical cutting force formula of turning SiCp/Al composites is established, and this formula takes SiC particles into account.3.Turning experiments of SiCp/Al composites are conducted. From the experiments' results, the biggest influence on cutting force is the depth of cut, followed by the feed rate, cutting speed has less effect. Consistent with the theoretical analysis, with the volume fraction of SiC particles increases, cutting forces become bigger, too. Under the same experiment condition, smaller cutting forces are gained when use PCD tools for turning the material than using carbide tools.4.Both conventional exponential empirical formulas and ternary quadratic regression empirical formulas of cutting force are established by analyzing experimental data. Compare their fit degree and forecast accuracy, it shows that under some certain circumstances, ternary quadratic formula is more suitable for fitting cutting force of turning SiCp/Al composites.5.Methods of predicting cutting force are researched. Attempt of applying support vector machine(SVM) algorithm to predict cutting force are made. Use the experimental data for training and predicting, then analyze the accuracy of prediction results, it shows that the prediction error is within the tolerance range, which indicates SVM algorithm can predict cutting force of turning Si Cp/Al composites efficiently and relatively accurately.