Investigation of microstructure and microhardness of pure W and W-2Y₂O₃ materials before and after ion-irradiation

Abstract

Pure W and W-2Y₂O₃ materials were fabricated using powder metallurgy method. The microstructures of the materials were investigated by electron back-scattered diffraction and transmission electron microscopy techniques. Both materials contain 1–2 μm size W grains. In the case of W-2Y₂O₃, the material contains yttria particles having sizes between 300 and 900 nm. The W matrix in W-2Y₂O₃ shows stronger texture than that of pure W. Berkovich hardness values are 4.5 GPa in pure W and 4.9 GPa in W-2Y₂O₃ for a 10 N load. Ion irradiation experiments were performed on both materials at the JANNuS facility (Saclay, France) using Fe and He ions with energies of 24 MeV and 2 MeV, respectively. Radiation loops are present on the W grains whereas on yttria particles, radiation-induced damages appear as voids. Berkovich hardness values of irradiated materials are slightly higher than the non-irradiated materials. Results of the microstructure and microhardness of irradiated as well as non-irradiated materials are presented in detail.