Experimental study on grinding process of Al-Mg 2 Si aluminum matrix composites

Abstract

As an aluminum-based reinforcement, Mg₂Si particles have excellent properties such as high hardness, high melting point, and high elastic modulus compared with other reinforcements and are widely used in aerospace and automobile fields. However, there is little research on the cutting mechanism of this material. In order to explore the surface grinding mechanism of Mg₂Si/Al composites, Grinding simulation of low-volume fraction Mg₂Si/Al composites was carried out by ABAQUS, and the influence of different positions of matrix and particle removal on the surface quality of Mg₂Si/Al composites was expounded. The plane reverse grinding test was carried out by using CBN (boron nitride) grinding wheel. The L₁₆(4³) orthogonal test and three groups of single factor tests were designed. The orthogonal results show that the linear velocity of the grinding wheel has the greatest influence on the surface roughness, and the feed rate and grinding depth are significantly smaller. The range analysis shows that the optimal grinding parameters are: v_s= 35 m/s, v_w= 0.75 m/min, a_p= 0.015 mm. The regression equation for surface roughness was established by using MATLAB. The single factor results show that the surface quality is obviously improved by increasing the linear velocity of the grinding wheel and reducing the feed rate and grinding depth through the observation of the morphology of the processed specimen. The analysis results show that defects such as pits, protrusions, burrs, and a small amount of fish-scale-like on the machined surface are mainly caused by the linear velocity of the grinding wheel, the pulling force of the grinding wheel, and the adhesion of the debris. The defects such as particle micro-cracks, particle pull-out, and matrix cracking on the subsurface, are mainly caused by the compressive stress of the grinding wheel and the stress concentration of the particles. The research results have guiding significance for future composite material cutting research and actual cutting processing.