Investigating drilling characteristics of stir-squeeze cast Al6082 composites reinforced with MWCNTs

Abstract

Objective of current study is to examine the machining characteristics of Al6082 composites embedded with multi-walled carbon nanotubes (MWCNTs). Herein, chemical vapor deposition (CVD) technique was used to develop MWCNTs. Stir-squeeze casting method was used to develop 0.3 wt.%−1.2 wt.% MWCNTs/Al6082 composites. Morphology of MWCNTs was analyzed by field emission scanning electron microscopy (FESEM). FESEM analysis was performed for as-cast nanocomposites which showed uniform spreading of MWCNTs up to 0.9 wt.% and beyond that clusters of MWCNTs were observed. Hardness and tensile strength of nanocomposites were also measured to observe the impact of addition of MWCNTs. Al6082 composites reinforced with 0.9 wt.% of MWCNTs showed highest hardness and tensile strength. It is important to examine the drilling characteristics as CNT in tube form may become constraint if they are not uniformly distributed and may obstruct tool movement. CNC electric discharge machining (EDM) and CNC milling machine were used to perform the drilling operation on nanocomposites with varying cutting parameters. It was noticed that inclusion of MWCNTs enhanced material removal rate (MRR) and surface finish of composites owing to enhanced brittleness. Strong interfacial bonding between MWCNTs and Al6082 matrix reduced the delamination during drilling operation.