Optimizing the drilling process parameters of AZ91 based hybrid composites using TOPSIS and grey relational analysis

Abstract

AZ91 is a popular magnesium alloy that contains aluminum (Al), zinc (Zn), and small amounts of other elements that offers a good balance of mechanical properties and corrosion resistance, making it suitable for various applications such as automotive, aerospace, sports, and biomedical. The current research works focused on optimizing drilling process parameters such as cutting speed, feed rate, a set of standard tools, and biofriendly coolants against the surface roughness and axial thrust force for AZ91/ nano hBN/ micron TiB₂ hybrid composites. Taguchi L18 orthogonal array was used to design the drilling experiments. The axial thrust force and surface roughness of the drilled hole were observed as response of the experiments. Based on the results from TOPSIS and GRA, the optimal conditions were determined to be a spindle speed of 65 m/min, feed rate of 1 mm/rev, using a High-Speed Steel (HSS) tool, and Liquid Nitrogen (LN) coolant for 1 wt% of nano hBN in the hybrid composite. These parameters resulted in the lowest axial thrust force and surface roughness, highlighting their effectiveness in optimizing the drilling performance of AZ91/TiB2/hBN composites.