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 via mechanical alloying and sintering at 1400 °C for 1 h under Ar, H₂ gas flowing conditions were investigated. XRD patterns of the sintered samples revealed the presence of W, Ni and TiB₂ phases, whereas W₂B and NiTi phases were detected in the samples containing 4 wt.% and 5 wt.% TiB₂. 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 varying TiB₂ between 1 wt.% and 5 wt.%. Average W grain size in the sintered samples decreased with the addition of Y₂O₃ and TiB₂ particles, from 5.38 μm in the W–1 wt.% Ni sample to 0.8 μm 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.