Influence of Al2O3 and Si3N4 Nano-particulates on Fracture Toughness Behaviour of Sintered Aluminium.

Fracture toughness behaviour of [Al/Si₃N₄/Al₂O₃]_P Nanocomposites was examined in the current research work. The nanocomposites were fabricated using powder metallurgical route for various compositions under the compacting pressure of 12.06 MPa and at a sintering temperature of 650 °C. The fracture toughness for all sample compositions estimated for longitudinal direction was accessed through apparent fracture toughness (K_Q), Equivalent energy fracture toughness (K_ee) and J integral (J) measurement. The result revealed the exceptionally good fracture toughness parameters (K_Q-17.6 MPa√m, K_ee-20.5 MPa√m and J integral-3.9 kJ/m²) of 2 wt% mixed Al₂O₃ and Si₃N₄ as compared to the pure sintered sample (K_Q-10.7 MPa√m, K_ee-13.4 MPa√m and J integral-1.0 kJ/m²). The fracture toughness parameters for 2 wt% mix Al₂O₃ and Si₃N₄ were observed to be maximum out of all sample compositions ranging from P to M₃, substantiating the role of transgranular ductile fracture mechanism as compared to the rest of the samples where the transgranular brittle fracture was dominant. [ABSTRACT FROM AUTHOR]