Fabrication and machinability analysis of squeeze cast Al 7075/h-BN/graphene hybrid nanocomposite

Abstract

This article deals with fabrication and machinability analysis of squeeze cast Al 7075/h-BN/Graphene hybrid nanocomposite (HNC), which has been fabricated by reinforcing hexagonal boron nitride (0.5 wt% h-BN) and graphene nanoparticles (1 wt% GNPs). In order to utilize the self-lubricating property of h-BN and GNPs, their uniform mixing is essential, hence before squeeze casting of HNC ball milling (BM) technique has been employed which enables uniform mixing and also eliminates the agglomeration effect of nanoparticles. Scanning electron microscopy (SEM) and optical microscopic (OM) investigation confirm the uniform mixing of nanoparticles as well as refinement in the grain size. In order to examine the hardness of the proposed HNC, mechanical properties were investigated and observed improvement of 31.25%, 10.93% and 10.27% in the UTS, microhardness (Vickers) and Rockwell hardness respectively as compared to unreinforced Al 7075 alloy fabricated by stir casting. Based on the obtained results machinability analysis is performed considering numerous machining process parameter during CNC turning to investigate the influence of cutting speed (CS), feed rate (FR) and depth of cut (DOC) on surface roughness (SR), generated forces, tool wear and chip morphology of squeeze cast HNC subjected to dry and minimum quantity lubrication (MQL) machining. Finally, the acquired results are presented with the aid of comparative graphical presentation with squeeze casted conventional aluminium alloy.