A study of mechanical properties and WEDM machinability of spark plasma sintered ZrB-BC ceramic composites.

Four different compositions of ZrB-BC composites (i.e., 5, 15, 20, 25 Wt. % of BC) were fabricated by Spark Plasma Sintering Technique (SPS) at 2000 °C temperature. The composites were characterized by the evolution of physical and mechanical properties; X-Ray Diffraction (XRD) analysis was also done for phase analysis of the composites. The relative density values were obtained in the range of 96.14-97.78 % of all the composites. The addition of BC in ZrB matrix led to an enhancement in hardness (15.38 GPa at 5 wt.% BC to 20.49 GPa at 25 wt.% BC measured at 1.0 kgf load) and fracture toughness (from 2.93 MPa-m at 5 wt.% BC to 4.13 MPa-m at 25 wt.% BC measured at 1.0 kgf load). The composite samples were processed by wire electrical discharge machining (WEDM) process with three different parameters set for the study of machining speed, surface roughness. The composite with 25 wt.% of BC shows highest machining speed of 10.56 mm/min. The average surface roughness (R) of the WEDM processed composite surfaces lies in the range of 1.26-5.64 μm.