Effects of ball milling parameters on microstructural evolution and mechanical properties of W-3% Y composites

Abstract The W-3 Y composites were successfully prepared by spark plasma sintering of milled W-3 Y powders with different milling times (0 h, 5 h, 15 h, 30 h). X-ray diffraction (XRD), scanning electron microscope (SEM), and laser particle size analysis were used to study the microstructural evolution and morphological change during the milling process. The crystallite sizes exhibited a continuous refinement along with the increased milling time. The median particle sizes, measured by the laser diffraction method, showed a similar change tendency. Due to the existence of Y particles, the W–Y milled powders exhibited spherical-like morphology while pure tungsten milled powders exhibited lamellar morphology at the early milling stage (5–15 h). The microhardness of W-3 Y compacts showed a slight increase with the increase of milling time. The maximum bending strength of 795 MPa was obtained by sintering W-3 Y powders milled for 15 h. As the milling time was prolonged to 30 h, the increased oxygen impurity resulted in a slight decrease of density as well as the degradation of bending strength.