Effect of microwave curing process on the flexural strength and interlaminar shear strength of carbon fiber/bismaleimide composites

Microwave heating has been conceived as a rapid and cost-effective method for curing carbon fiber composites. In this paper, microwave radiation was used to cure carbon fiber/bismaleimide composites aiming at shortening the production cycle time. Through controlling the microwave power, vacuum bagged laminates were fabricated under one atmosphere pressure without arcing. Degree of cure, void content and fiber volume fraction were measured to evaluate part quality. Three-point flexure and short beam shear testing were employed for mechanical assessment. Variation in the microwave cure cycle had a significant effect on the material properties. The optimum processing parameters for microwave curing were established based on analysis of the mechanical performance. A cycle time reduction of nearly 63% was obtained compared to thermal processing. The physical and mechanical properties of microwave cured samples were found to be superior to those cured in a conventional oven. The composite panels manufactured by the optimized microwave cure process exhibited a slight decrease in flexural strength but equivalent interlaminar shear strength in comparison with those produced by autoclave curing.