Assessment of ultrasonic drilling of C/SiC composite material

Ultrasonic drilling of two-dimensional carbon fiber-reinforced silicon carb ide(C/SiC) composites was investigated in this study. The composites were m ade through a polymer pyrolysis route. X-ray diffraction was adopted to exa mine the formation of crystalline structure in the matrix of the fabricated composites. Density and porosity, and flexural strength were measured to s tudy the densification efficiency and the mechanical properties, respective ly, of the C/SiC composites fabricated under various conditions. The fractu re morphologies were also examined by scanning electron microscopy to inves tigate the fracture behavior of the composites under flexural test. The eff ects of various parameters of ultrasonic drilling, including abrasives, vol ume ratio, electric current and down-force, on the material removal rate, h ole clearance, edge quality and tool wear are presented and discussed. Opti mal operating conditions are identified. In comparison with other feasible machining processes, ultrasonic drilling for this composite material posses ses advantages concerning machinability and cost. (C) 2000 Elsevier Science Ltd. All rights reserved.