Fabrication and properties of mechanically alloyed and Ni activated sintered W matrix composites reinforced with Y2O3 and TiB2 particles

Microstructural and physical properties of W-1 wt% Ni matrix composites reinforced with Y2O3 and TiB2 particles produced by mechanical alloying and sintering at 1400 C for 1 h under Ar, H2 gas flowing conditions were investigated. XRD patterns of the sintered samples showed the presence of W, Ni and TiB2 phases, whereas W2B and NiTi phases were detected in samples containing 4 wt% and 5 wt% TiB2. The relative density value of W-1 wt% Ni sample was measured as 97%, which decreased to 95.4% with the addition of 0.5 wt% Y2O3. Relative density values varied between 95.4% and 97.3% for the sintered samples containing TiB2 varying between 1 wt% and 5 wt%. The average W grain size in the sintered samples decreased with the addition of Y2O3 and TiB2 particles, from 5.38 micron in the W-1 wt% Ni sample to 0.8 micron in the W-1 wt% Ni sample containing 0.5 wt% Y2O3 and 5 wt% TiB2 particles. Vickers microhardness values varied between 4.53 GPa and 8.54 GPa. The sample with the composition of W-1 wt% Ni/0.5 wt% Y2O3 and 5 wt% TiB2 had a relative density value of about 95.7% and hardness value of 8.54 GPa after sintering at 1400 C for 1 h.