Material Removal Mechanism in Machining SiC_p/Al Composite with High Volume Fraction of SiC_p

A two-dimensional cutting simulation model of 60vol% SiC_p/Al composite with random distribution of irregular pentagonal and hexagonal SiC particles was established, and the material removal mechanism of the composite was explored in conjunction with milling experiments. The effects of cutting speed (1, 3, 5, 7, 9 m · s⁻¹) and blunt radius of the cutting edge of the tool (10, 15, 20, 25, 30 μm) on cutting force and surface quality of the composite were analyzed by simulation. The results show that the average cutting force under the cutting speed of 1 m · s⁻¹ and the blunt radius of the cutting edge of 10 μm simulated by the two-dimensional cutting simulation model was 16.40 N, and the relative error between the simulation and the test result was 14.67%, verifying the accuracy of the simulation method. During cutting of the composite, SiC particles hindered the movement of dislocations, causing cracks to initiate and propagate at the particle/matrix interface, and eventually chips were formed. The high ductility of the aluminum matrix, the relative position of the particles and the cutting tool, as well as particle fracture, debonding at the particle/matrix interface, particle being pulled out and particle being pressed into the matrix were the main causes of damage such as scratches, pits, rough particle cross-sections, matrix tearing and cavities on the processing surface of the composite. As the cutting speed or the blunt radius of the cutting edge increased, the cutting force when machining the composite increased, the roughness of the machined surface increased, and the quality of the machined surface was deteriorated.