Fabrication and characterization of nanocrystalline ODS-W via a dissolution-precipitation process

In this paper, high density nanocrystalline W with uniform dispersion of nanosized oxide particles was fabricated via a dissolution-precipitation process by well controlled high-energy ball milling of the raw powder materials of Y2O3, Ti and W and the subsequent spark plasma sintering (SPS). XRD and TEM analysis revealed that the Y2O3 and Ti were dissolved in W matrix during the high-energy ball milling and the Y2Ti2O7 particles were precipitated in the SPS process, resulting in the refinement in both W grains and oxide particles. The average grain size of W is 67 nm. The average size of particles in grain interior and at grain boundaries is 8.5 nm and 16.4 nm, respectively. The Vickers microhardness of such a nanostructured W alloy is as high as 1441 Hv, which is 2-3 times that of the ever reported W alloys. Such a dissolution-precipitation process offers a general pathway for manufacturing nanocrystalline refractory metals with dispersion of nanoscale oxides in a controllable manner.