HIGH-TEMPERATURE DEFORMATION OF A MECHANICALLY ALLOYED NIOBIUM-YTTRIAALLOY

Mechanical alloying (MA) and hot isostatic pressing have been used to process two Nb alloys containing yttria particles, Nb-2vol.%Y2O3 and N b-10vol.%Y2O3. Similar to some thermomechanically processed nickel-bas ed alloys, both alloys exhibit partially recrystallized microstructure s, consisting of a 'necklace' of small recrystallized grains surroundi ng much larger but isolated, unrecrystallized, cold-worked grains. Hot compression tests from 1049 to 1347 degrees C (0.5-0.6T(MP)) of the 1 0% Y2O3 alloy show that MA material possesses a much higher yield and creep strength than its powder-blended, fully recrystallized counterpa rt. In fact, the density-compensated specific yield strength of the MA Nb-10Y(2)O(3) exceeds that of currently available commercial Nb alloy s.