Production of SiC and B4C particle reinforced aluminum matrix composites by powder metallurgy method and improvement of hole quality

In this study, Al/SiC and Al/B4C/SiC composite materials were produced using the direct hot-pressing technique, which is one of the powder metallurgy methods, at a pressure of 35 MPa, a temperature of 600°C, and a duration of 5 minutes. Particle size and SEM analyzes of the powders used (Al, B4C and SiC) were carried out. The microstructure, mechanical properties and drillability of the produced Al matrix composites were investigated. It was observed that the density decreased, the macro and microhardness values increased, and the transverse rupture strength decreased with the increase of the reinforcement ratio. Drilling experiments were carried out in accordance with the Taguchi L18 experimental design. Control factors are cutting speed (i.e., 25 and 50 m/min), feed rate (i.e., 0.08, 0.16 and 0.24 mm/rev), point angle (i.e., 100°, 118° and 136°), and SiC reinforcement ratio (i.e., 0%, 5% and 10%) were selected. The quality characteristics were determined as thrust force, torque, surface roughness, deviation from diameter and deviation from circularity. Single-response and multi-response optimization were performed to improve the hole quality of the developed materials. Taguchi method was used for single-response optimization, and Entropy-weighted Taguchi-based GRA, TOPSIS and CoCoSo methods were used for multi-response optimization. The effect of control factors on quality characteristics was determined by ANOVA test. In addition, regression analysis was applied to establish a mathematical relationship between control factors and quality characteristics. It was observed that the R2 values obtained from the regression equations were quite high. This showed that the predictive ability of the developed model is strong. Confirmation experiments were carried out under optimum experimental conditions. The data obtained from the validation experiment results were found within the confidence interval limits at the 95% confidence interval and 5% significance level. As a result, when the drillability of the produced composite materials was examined, it was determined that the B4C and SiC reinforced hybrid composite performed better than the SiC reinforced composite material.