Effect of sintering parameters on microstructure and mechanical properties of self-lubricating functionally graded cemented tungsten carbide

Modern-day industries are showing enormous attention towards green and clean manufacturing; subsequently, research on self-lubricating cutting tool material is in vogue. To deal with the incompatibility between the tribological and mechanical properties of monolithic self-lubricating cemented tungsten carbide, a functionally graded cemented tungsten carbide with solid lubricant gradient (CaF2) was developed using Spark Plasma Sintering. The attempts were made to optimize sintering condition and characterize their effect over mechanical and microstructure properties. The comparative study between different sintering conditions showed that best material properties are obtained at 1150 degrees C sintering temperature, 100 degrees C/min heating rate, 10 min soaking time and 50 MPa pressure. The hardness and fracture toughness increases with sintering temperature and heating rate. Also, the nature of residual stresses changes from compressive to tensile from the surfaces to core. All these material behaviors are essential for cutting tool material and exhibit enormous potential for application in dry machining.