Optimizing ball milling duration for microstructural homogeneity and interfacial bonding in Mg-HA-graphene nanocomposites for biomedical implants

This study investigates the influence of ball-milling duration (2, 4, 6, and 8 hours) on the structural integrity, interfacial bonding, and microstructural uniformity of Mg-HA-graphene nanocomposites (Mg-92 wt%, HA-6 wt%, GNP-2 wt%). Comprehensive characterization via particle-size analysis, XRD, XPS, and SEM/EDS revealed that milling duration profoundly governs both phase distribution and interface chemistry. An optimal balance was achieved at 6 hours of milling, which produced the smallest average crystallite size ( ), reduced microstrain, and the most homogeneous HA/GNP dispersion without introducing unwanted secondary phases. XPS deconvolution showed a well-defined phosphate (P 2p) and calcium (Ca 2p) environment, reduced Mg-oxide formation, and preserved graphitic C-C bonding, confirming robust chemical stability. These findings demonstrate that controlled intermediate milling enhances interfacial cohesion, mechanical homogeneity, and the structural reliability of biodegradable Mg-based hybrid composites.