The reinforcing effect of graphene nano-platelets on the cryogenic mechanical properties of GNPs/Al2O3 composites

The mechanical properties of the graphene nano-platelets reinforced alumina nanocomposites at cryogenic temperature are reported for the first time. The GNPs/Al2O3 composites are fabricated by a colloidal process. The temperature-dependent increase in hardness is accompanied by a substantial increase in fracture toughness with the temperature decreasing from 293 K to 77 K. The optimum content of GNPs in GNPs/Al2O3 composites is 1.0 vol%. The effect of residual stress on the toughness and fracture mode is discussed on the basis of theoretical calculation and analysis. Cryogenic temperature has contributed to the reinforcing effect of graphene in composites.