Development of an ultra-fine grained V-1.7 mass% Y alloy dispersed with yttrium compounds having superior ductility and high strength

In order to develop an ultra-fine grained vanadium alloy dispersed with nano-sized dispersoids having superior ductility and high strength, powder metallurgical methods utilizing mechanical alloying (MA) and hot isostatic pressing (HIP) processes were applied to vanadium with 1.7 mass% yttrium addition. The developed alloy was annealed at 1273-1573 K for 3.6 ks and subjected to TEM observations and tensile tests at room temperature. The alloy has average grain sizes from 330 to 750 nm, and average particle sizes of Y2O3 and YN from 7 to 23 nm, depending on annealing temperature. It exhibits superior ductility and high strength even in the as-HIPed state (no plastic working). Eighty percent cold rolling slightly improves the tensile properties. These results indicate that the microstructure of the alloy is almost free from weak portions associated with gaseous interstitial impurities that cause significant loss of ductility. (c) 2005 Elsevier B.V. All rights reserved.