Effect of ion-irradiation on the microstructure and microhardness of the W-2Y(2)O(3) composite materials fabricated by sintering and hot forging

A W-2Y(2)O(3) material was developed in collaboration with the Plansee Company (Austria). An ingot of the material having approximate dimension of 95 mm x 20 mm was fabricated by mixing the elemental powders followed by pressing, sintering and hot forging. The microstructure of the W-2Y(2)O(3) composite was investigated using transmission electron microscopy (TEM). The microhardness wasostudied using nano-indentation technique. We observed that the W-grains having a mean size of about 1 mu m already formed and these grains contain very low density of dislocations. The size of the yttria particles was between 300 nm and 1 mu m and the Berkovich hardness was about 4.8 GPa. The specimens were irradiated/implanted with Fe and He ions at JANNuS facility located at Orsay/Saclay, France. The TEM disks kept were irradiated/implanted at 300 and 700 degrees C using Fe and He ions with an energy of 24 and 2 MeV, respectively. The calculated radiation dose was about 5 dpa produced by Fe ions and total He content is 75 appm at both 300 and 700 degrees C. From the TEM investigation of irradiated samples, few radiation loops are present on the W grains, whereas on yttria particles, the radiation induced damages appear as voids. Berkovich hardness of the irradiated sample is higher than that of the non-irradiated sample. Results on the microstructure and microhardness of the ion-irradiated W-2Y(2)O(3) composites are presented in detail. (C) 2013 Elsevier B.V. All rights reserved.