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

Ağaoğulları D., BALCI O., GOKCE H., Öveçoğlu M. L., Duman I.

INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, vol.41, pp.577-584, 2013 (SCI-Expanded) identifier identifier


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.