Abstract
1 vol% Ni particulate Al2O3 matrix nanocomposites prepared by the heterogeneous precipitation method with ZrO2 (5 vol%) or Cr2O3 (1 vol%) additives were subjected to the low energy drop weight impact tests to compare the behavior of the compositions under low energy impact and to investigate the damage mechanisms. The pure Al2O3, Al2O3/Ni, Al2O3/ZrO2, and Al2O3/Cr2O3 compositions with the same additive ratios were also produced to make the comparison systematically. Also, the Vickers hardness measurements were carried out and a significant increase in hardness was attained for both Al2O3/Ni + ZrO2 and Al2O3/Ni + Cr2O3. The average hardness value around 24.8 ± 1.0 GPa was measured for Al2O3/Ni + ZrO2 and Al2O3/Ni + Cr2O3 which means ∼ 15% improvement compared to the pure Al2O3. Between all the compositions, the maximum force (Fmax) value was obtained for Al2O3/Ni + ZrO2 for 12 J impact energy level (26617 N) according to the low energy drop weight impact test results. Tensile radial crack network formation, cone formation, fracture and crushing of the cone structure were observed as damage mechanisms for all the compositions. The volume of conical frustum structure was evaluated for each composition and the effect of microstructure on possible ballistic performance was also discussed.
A new drop weight impact machine for studying the fracture behaviour of structural concrete
