Investigation of surface integrity transition of SiCp/Al composites based on specific cutting energy during ultrasonic elliptical vibration assisted cutting

Different from brittle materials or homogeneous metal materials, there is no obvious characteristic of brittle removal or plastic removal in machining of particle reinforced metal matrix composites (MMCs). In the present work, we investigate the surface integrity transition of SiCp/Al composites during ultrasonic elliptical vibration-assisted cutting (UEVC). The machined surface is divided into two parts: plastic deformation of metal matrix and defects caused by particle deformation. A specific-cutting-energy-based criterion based on the relationship between plastic deformation and defects formation, is established to characterize the surface integrity transition of SiCp/Al composites quantitatively. The effectiveness of the critical cutting parameter is verified by systematic experiments. Experimental results show that the surface integrity transition of SiCp/Al composites is mainly affected by processing method and cutting speed. When the scratching speed increases from 100 mm/min to 200 mm/min, the main part of machined surface changes from defects to plastic deformation accordingly in UEVC. The ductile surface of SiCp/Al composites can be obtained when the cutting speed, cutting depth and feed rate are 100 mm/min, 0.01 mm and 0.02 mm/rev, respectively. According to the experimental results, particle partial fracture, debonding and micro-deflection dominate particle removal process in UEVC, which is also the main reason why UEVC can improve the machinability of SiCp/Al composites.