Effects of Al2O3 addition on the microstructure and properties of Ni activated sintered W matrix composites

Demirkan O. U., GENC A., Öveçoğlu M. L.

INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, vol.32, pp.33-38, 2012 (SCI-Expanded) identifier identifier


In the present investigation, fabrication of high dense (>97.8%) W matrix composites with increased microhardness values were investigated. W and W-1 wt.% Ni powders were mechanical alloyed for 18 h and sintered at 1400 degrees C for 1 h under Ar, H-2 gas flowing conditions in order to investigate the effects of 1 wt.% Ni addition on the densification and properties of W. The effects of Al2O3 particles additions on the microstructural and physical properties of the sintered W-1 wt.% Ni sample were investigated. A 92.59% relative density value of the sintered W sample increased to 99.47% with the addition of I wt.% Ni. Moreover, despite the observed grain growth, microhardness values significantly increased from 2.81 +/- 0.34 GPa to 4.07 +/- 0.16 GPa with the addition of 1 wt.% Ni. The relative density values of the sintered W-1 wt.% Ni sample slightly decreased with increasing Al2O3 additions, a relative density value of 97.81% was measured for the W-1 wt.% Ni sample reinforced with 2 wt.% Al2O3 particles. As the average grain size of W in the sintered W-1 wt.% Ni sample decreased from 4.41 +/- 1.71 pm to 1.29 +/- 0.39 mu m with the addition of 2 wt.% Al2O3 particles, the microhardness of the sample increased to 5.98 +/- 0.31 GPa. (C) 2012 Elsevier Ltd. All rights reserved.