Difficult-to-cut materials have been widely employed in many engineering applications, including automotive and aeronautical designs because of their effective properties. However, other characteristics; for example, high hardness and low thermal conductivity has negatively affected the induced surface quality and tool life, and consequently the overall machinability of such materials. Inconel 718, is widely used in many industries including aerospace; however, the high temperature generated during machining is negatively affecting its machinability. Flood cooling is a commonly used remedy to improve machinability problems; however, government regulation has called for further alternatives to reduce the environmental and health impacts of flood cooling. This work aimed to investigate the influence of dispersed multi-wall carbon nanotubes (MWCNTs) and aluminum oxide (Al₂O₃) gamma nanoparticles, on enhancing the minimum quantity lubrication (MQL) technique cooling and lubrication capabilities during turning of Inconel 718. Machining tests were conducted, the generated surfaces were examined, and the energy consumption data were recorded. The study was conducted under different design variables including cutting speed, percentage of added nano-additives (wt.%), and feed velocity. The study revealed that the nano-fluids usage, generally improved the machining performance when cutting Inconel 718. In addition, it was shown that the nanotubes additives provided better improvements than Al₂O₃ nanoparticles.

The nexus of sustainable manufacturing and Industry 4.0 technologies is redefining modern industrial practices. Conventional manufacturing, characterized by intensive energy use, resource depletion, and waste generation, is increasingly unsustainable in the face of environmental pressures and evolving regulations. Industry 4.0 technologies—including IoT, artificial intelligence, data analytics, cloud computing platforms, and, recently, digital twins—provide opportunities to embed sustainability by enabling real-time monitoring, predictive analytics, and adaptive decision-making. This paper addresses key methods and strategies for sustainability and Industry 4.0 nexus. It involves IoT systems for data-driven monitoring, AI for process optimization, cloud platforms for supply chain sustainability, and emphasizes the use of digital twins for predictive maintenance. Organizational strategies such as cross-functional collaboration, customized software, dual-focus performance metrics, and workforce reskilling are explored, alongside barriers including high capital costs, cybersecurity risks, and system integration challenges. The findings present a structured perspective on harmonizing sustainability and Industry 4.0, demonstrating how this nexus can reduce environmental impact, enhance efficiency, and support long-term industrial resilience.