Effect of graphene nanoplatelets on the mechanical properties and cutting performance of alumina nanocomposite ceramic tools prepared using the SPS-HF dual sintering method.

Al 2 O 3 /graphene nanoplatelets (GNPs) materials were prepared using the spark plasma sintering-high-frequency (SPS-HF) dual sintering method. The mechanical properties and microstructure of the composites were observed, and the effects of the sintering process and GNPs on the composites were analyzed. Under the sintering condition of a temperature of 1350 °C, pressure of 35 MPa and holding time of 8 min, the optimal mechanical properties of Al 2 O 3 ceramic tool materials were obtained. The addition of GNPs had a positive effect on the mechanical properties of Al 2 O 3 materials. Results show that the SPS-HF dual-sintering method shortens sintering time significantly. Compared to Al 2 O 3 ceramic material, the composite material with 0.5 vol% GNPs had better mechanical properties than the Al 2 O 3 ceramic material, with its flexural strength and fracture toughness being increased by 15.3% (617 MPa) and 63.4% (6.7 MPa m1/2), respectively. The toughening mechanisms of Al 2 O 3 /GNPs ceramic nanocomposites are graphene pull-out, graphene breaking, crack deflection, and crack branching. Dry machining tests of 40Cr hardened steel were carried out using an Al 2 O 3 /GNP ceramic tool and an Al 2 O 3 ceramic tool. Compared with the Al 2 O 3 ceramic tool, the life of the Al 2 O 3 /GNPs ceramic tool was increased by 16.3%, the workpiece roughness was decreased by 9.2%, and the friction coefficient was reduced by 12.8%, confirming the improvement of cutting performance by adding GNPs to ceramic tool materials. [ABSTRACT FROM AUTHOR]