Comparative investigations of the activated sintered W-1 wt.% Ni composites reinforced with various oxide and boride particles

The effects of different kinds of oxide (La₂O₃ and Y₂O₃) and boride (CrB₂, HfB₂ and ZrB₂) particles on the physical, microstructural and mechanical properties of the W-1 wt.% Ni matrix composites were investigated. Powder blends having compositions of W-1 wt.% Ni, W-1 wt.% Ni-1 wt.% x, and W-1 wt.% Ni-1 wt.% x-2 wt.% y (x = La₂O₃ and Y₂O₃; y = CrB₂, HfB₂ and ZrB₂) were mechanically alloyed (MA'd) for 12 h in a Spex™ Mixer/Mill with a rate of 1200 rpm using tungsten carbide vial and balls. MA'd powders were compacted to cylindrical preforms in a hydraulic press under a uniaxial pressure at 400 MPa and the green compacts were sintered at 1400 C for 1 h under Ar/H₂ gas flowing conditions. Phase and microstructural characterization investigations of the MA'd powders and sintered composites were performed using X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) techniques. Density, Vickers microhardness and sliding wear tests were conducted on the sintered samples. The simpler systems of the hybrid composites (W-1 wt.% Ni, W-1 wt.% Ni-1 wt.% La₂O₃ and W-1 wt.% Ni-1 wt.% Y₂O₃) yield inferior mechanical properties than those of the hybrid composites. Among the fabricated hybrid composites, W-1 wt.% Ni-1 wt.% La₂O₃-2 wt.% CrB ₂ had the highest density value of 98.89% and W-1 wt.% Ni-1 wt.% La₂O₃-2 wt.% HfB₂ had the highest microhardness value (7.97 ± 0.50 HV) and the lowest relative wear volume loss (0.37).