Machinability assessment of a graphene-reinforced ADC12 aluminium composite: Effects of tool coatings and cutting parameters on cutting force and surface roughness

Graphene-reinforced aluminium metal matrix composites (MMCs) have significant potential for lightweight applications. However, limited studies have investigated the end milling of stir-cast graphene-reinforced ADC12 aluminium composites, particularly comparing uncoated, TiC chemical vapour deposition (CVD)-coated, and TiNbN physical vapour deposition (PVD)-coated carbide inserts using response surface methodology (RSM) and analysis of variance (ANOVA). This study investigates the machining performance of graphene nanoplatelet-reinforced ADC12 aluminium composites using these three types of carbide inserts. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirmed the incorporation and distribution of graphene within the aluminium matrix. The results revealed that cutting speed, feed rate, and insert type significantly influenced machining performance. Cutting speed and insert type predominantly affected surface roughness, whereas feed rate had the greatest influence on cutting force. The TiNbN PVD-coated insert outperformed the other tools, producing the lowest cutting forces and best surface finish. The minimum cutting force of 52.320 kgf and surface roughness of 2.278 µm were achieved at a cutting speed of 3000 rpm and feed rate of 1250 mm/min. Although the TiC CVD-coated insert exhibited stable performance under high machine loads, comparatively higher cutting forces and surface roughness were observed under certain conditions. The statistically significant quadratic models demonstrated satisfactory predictive capability. These findings highlight the importance of tool selection and machining parameter optimisation in improving the machinability and surface integrity of graphene-reinforced ADC12 aluminium composites.