Experimental investigation of dry turning on SPS-processed Ti5Al4V matrix composite with TiBw reinforcement using multilayered PVD-coated AlTiN + TiN,TiSiCrN + TiN,and MoS 2  + TiN tools

Abstract

This research explores how advanced multilayer coatings – AlTiN + TiN, TiSiCrN + TiN, and MoS₂ + TiN – enhance the performance of cutting inserts during the turning of Ti5Al4V composites reinforced with TiBw, processed by spark plasma sintering. The objective of the research is to use a robust multilayer physical vapour deposition (PVD) coating to create a strong thermal shield that protects the cutting tool while maintaining its strength and resilience during hard-material turning, and to develop a superior material for high-temperature applications. The investigation highlights the remarkable performance of the MoS₂ + TiN-coated insert, which delivers an exceptionally low average Ra of 0.1002 μm, far surpassing the average surface roughness values of TiSiCrN + TiN and AlTiN + TiN. The investigation compares essential parameters, including cutting speed, feed and depth of cut, chip–tool contact area, chip thickness, flank wear, power consumption, and tool life. As machining length increases, all coated inserts experience greater flank tool wear. Among the coatings, AlTiN + TiN stands out with the least wear at 360.36 μm, followed by TiSiCrN + TiN at 392.81 μm, while MoS₂ + TiN shows the highest wear at 559.19 μm at the end of the turning process. The High-Resolution Scanning Electron Microscope (HRSEM) is used with a Kistler 9263 dynamometer to assess wear behaviour and cutting forces of the cutting tool. Findings indicate that all coating layers serve as thermal barriers, preventing excessive heat buildup in the cutting tool. Consequently, this enhances surface quality, tool durability, and overall efficiency while reducing abrasive wear, tear, and parallel ridges caused by rubbing friction. Moreover, it has been determined that a multilayer AlTiN/TiN coating yields consistent results with minimal tool wear, particularly under elevated-speed turning conditions. The findings of this research substantiate the effectiveness of coated tool inserts for high-speed dry cutting processes.