High Temperature Tensile Properties And Their Application To Toughness Enhancement In Ultra-Fine Grained W-(0-1.5)Wt% Tic

Ultra-fine grained (UFG) W-TiC consolidates are very promising for use as divertors in fusion reactors, however, the assurance of room-temperature ductility of UFG W-TiC remains unsettled. The assurance requires a sufficient degree of plastic working for the consolidates and thus overcoming of poor plastic workability in UFG W-TiC by applying superplasticity. Therefore, the magnitudes of elongation to fracture and flow stress which are important measures for plastic working were examined for UFG W-(0-1.5)%TiC (in wt%) at 1673-1973 K where superplasticity occurs without appreciable grain growth. It is shown that the elongation and flow stress are strongly dependent on TiC addition and atmosphere (Ar, H-2) during mechanical alloying (MA). As the TiC addition increases, the elongation significantly increases without appreciable increase in the flow stress level. W-TiC fabricated with MA in H-2 exhibits larger elongation and larger strain rate sensitivity of flow stress than W-TiC with MA in At. These results were applied to perform plastic working and the room-temperature bend test results for plastic worked W-1.0%TiC are shown. (C) 2008 Elsevier B.V. All rights reserved.