Fabrication of FeNi–Al2O3 nanocomposites and optimization of mechanical properties using Taguchi method

FeNi–Al2O3 composites are under attention for many applications because of their good magnetic properties, high strength and fracture toughness and excellent corrosion and wear resistance. In the current study, FeNi–Al2O3 nanocomposite powders were synthesized through mechanical alloying of Fe2O3, Al and Ni powder mixture. Bulk samples were prepared under subsequent cold pressing and sintering processes. Study of the phase evolution using SEM, EDS and XRD showed that FeNi matrix nanocomposites reinforced with 10, 15 and 30 wt.% of Al2O3 were fabricated in 300, 240 and 180 min of milling, respectively. Mean crystallite size of FeNi phase at these samples after 720 min milling was calculated about 28, 35 and 22 nm, respectively. Effect of various parameters such as Al2O3 weight percentage, uniaxially cold pressure, sintering temperature and sintering time on the fabrication (densification and consolidation) and mechanical properties (hardness, compression strength and specific wear rate) of these nanocomposites was investigated. Because of numerous experiments needed, design of experiment based on Taguchi method was applied. Considering optimized condition offered by analysis of variance (ANOVA), maximum density (5.314 g/cm3), maximum hardness (786 HV), maximum compression strength (97.76 MPa) and minimum specific wear rate (0.0251 mm3/Nm) of FeNi–Al2O3 nanocomposites were obtained.