Optimization on machining parameters of aluminium alloy hybrid composite using carbide insert

Abstract

In this experimental work, three different aluminium alloy based composites were developed by using Al 6061, AA 2024 and AA 7075 as matrix materials and Graphene (2 wt%) as reinforcement material. The fabrication of nano composites were carried out using powder metallurgy route followed by hot extrusion. The extruded samples of the three composites were subjected to turning experiments to explore its machinability. Five parameters namely, type of work material, cutting tool material, cutting speed, feed rate and depth of cut are considered for the turning experiments. Taguchi L18 mixed orthogonal array with three levels of cutting speeds (35, 50 and 65 m min−1), feed rates (0.1, 0.2, 0.3 mm/rev), depth of cut (0.6, 0.8, 1 mm), three different work (composite) materials and two levels of cutting tool (Uncoated and DLC Coated carbide) materials was used for the design of experiment. Cutting force generated during the machining process, surface roughness and surface hardness obtained on the machined surface of the specimen and flank wear on the tool subsequent to machining are recorded for further analysis. Analysis of Variance (ANOVA) was carried out using the experimental data to determine the significance of each variable parameter on the response parameter. From ANOVA, it has been noted that AA6061 based composite has encountered significant cutting force when compared to other two composite. Likewise work material have more influence on surface roughness while comparing the other machining parameters and AA7075 based composite was found to result in better surface finish. Cutting speed has significantly influenced the flank wear followed by the tool material and it was found that uncoated carbide has undergone more wear than the DLC coated carbide insert. Further, it is evident from micro structural and FESEM analysis that there is a homogeneous distribution of Graphene particles in aluminium matrix after hot extrusion.