Preparation and cutting performance of (W,Ti,Ta)C/CaF2 2 nano-self-lubricating cermet tool material via spark plasma sintering

To improve the machining surface integrity of HT250 gray cast iron, (W,Ti,Ta)C based nano-self-lubricating cermet tools containing nano CaF2 2 were successfully prepared by spark plasma sintering (SPS). When the content of nano CaF2 2 was 5 vol%, the flexural strength, hardness, and fracture toughness of (W,Ti,Ta)C/CaF2 2 nano- self-lubricating cermet tool were 1134 +/- 39 MPa, 18.97 +/- 0.22 GPa and 8.52 +/- 0.33 MPa & sdot;m1/2, 1/2 , respectively. The cutting experiments were carried out by minimum quantity lubrication (MQL), and the effects of nano CaF2 2 content and MQL on cutting performance were studied. The cermet tool with 5 vol% nano CaF2 2 had the optimized cutting performance under MQL conditions, with cutting forces F X , F Y , and FZ Z reduced by 20.5%, 37.9%, and 33.3%, respectively, cutting temperature decreased by 34.8%, and tool life increased by 16.7%. The solid- liquid dual lubrication cutting method combined with the solid lubrication CaF2 2 and MQL effectively reduced the thickness and oxidation degree of the work hardening layer. The optimized surface roughness of the workpiece after machining was 0.89 +/- 0.05 mu m, which is 27.6% lower than that of dry cutting.