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 (TM) 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 degrees C for 1 h under Ar/H-2 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.% CrB2 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). (C) 2013 Elsevier Ltd. All rights reserved.