Effects of sintering parameters on microstructure, graphene structure stability and mechanical properties of graphene reinforced Al2O3-based composite ceramic tool material

Graphene reinforced Al2O3-based composite ceramic tool materials were synthesized using hot pressing (H) under sintering conditions of 1550-1750 degrees C sintering temperature, 5-30 min dwell time and 25-40 MPa appli pressure in order to investigate the effects of sintering parameters on microstructure, graphene structure stability and mechanical properties of composite ceramic tool materials. Sintering parameters of 1600 degrees C sinteril temperature, 15 min dwell time and 30 MPa applied pressure were demonstrated to be the optimal sintering parameters to obtain dense and refined microstructure. The wrapping mechanism of graphene on ceramic grains was believed to play a significant role in the formation process of this optimized microstructure. Based on Ram, spectrum analysis, graphene structure stability was subjected to sintering temperature and dwell time. Graphene structure could be destructed under the high sintering temperature or extended dwell time. And the shortened dwell time was also detrimental to graphene structure stability due to the lower crystallinity. Mechanic properties of composite ceramic tool materials were also optimized under the optimal sintering parameter Grain refinement and weak bonding interface induced by graphene were responsible for the improved fractu toughness.