The machinability of high-strength alloys, such as GTD-450, is noted for its severe difficulties, including higher tool wear and a poor surface finish, necessitating sophisticated, environmentally friendly lubrication techniques and the adequate selection of cutting parameters. Among high-resistant superalloys, limited work has been reported on the machining of GTD-450, particularly on the use of different lubrication strategies, lubricants, and nanoparticles. Therefore, in the course of this work, face milling of the GTD-450 was conducted using three different lubrication techniques: conventional Minimum Quantity Lubrication (MQL), MQL with added Al₂O₃ nanoparticles (Al₂O₃-NMQL), and MQL with added ZnO nanoparticles (ZnO-NMQL). A comparative assessment of tool wear size and average surface roughness (Ra) was conducted. The findings have revealed a significant dominance of nanofluid-based MQL over the conventional practice of classical MQL. In particular, ZnO-NMQL has been established as an optimal performing technique, reducing tool wear by an average of 15.48% and Ra by an average of 6.05% compared to the classical MQL-based technique. The Al₂O₃-NMQL technique has also achieved significant reductions, with tool wear reduced by 10% and surface quality improved by an average of 4.8%. The use of nanofluids, particularly ZnO, has proven significantly effective in minimizing Built-Up Edge (BUE) formation. At the final stage, multi-response optimization using a desirability function approach was conducted, yielding optimal machining parameters. The findings establish that ZnO-nanofluid MQL is an efficient and environmentally friendly approach for enhancing the machinability of GTD-450 steel, representing a promising step toward improved tool life and a better surface finish in practical cutting conditions.
Bakhshayesh et al. (2026) studied this question.