Surface integrity in machining of AZ91/SiC composites

Abstract

Use of metal matrix composites (MMC) is growing due to their high strength-to-weight ratio, resistance to wear, creep, etc. Machining of metal-matrix composites (MMC) faces many challenges, especially with regard to obtaining a finished surface with high quality. In this research, AZ91/SiC samples with different volume fractions are machined at different cutting conditions with respect to feed rate, cutting speed, and depth of cut. Surface integrity of the machined samples is analyzed by different methods such as tactile profilometer and 3D surface topography to investigate the SiC effects on the finished surface. Additionally, sample surfaces are evaluated by scanning electron microscope (SEM) and with energy-dispersive X-ray (EDS) to assess the surface defects formed around reinforcement materials. Results indicate SiC particles decline the surface quality and uniformity due to the formation of some defects such as micro cracks, holes, and undesired deformations when the cutting process. Also, subsurface SiC particles close to the machined surface are cracked after machining.