High-temperature deformation of a mechanically alloyed niobium-yttria alloy

Mechanical alloying (MA) and hot isostatic pressing have been used to process two Nb alloys containing yttria particles, Nb-2vol.%Y2O3 and Nb-10vol.%Y2O3. Similar to some thermomechanically processed nickel-based alloys, both alloys exhibit partially recrystallized microstructures, consisting of a ‘necklace’ of small recrystallized grains surrounding much larger but isolated, unrecrystallized, cold-worked grains. Hot compression tests from 1049 to 1347 °C (0.5–0.6 TMP) of the 10% Y2O3 alloy show that MA material possesses a much higher yield and creep strength than its powder-blended, fully recrystallized counterpart. In fact, the density-compensated specific yield strength of the MA Nb-10Y2O3 exceeds that of currently available commercial Nb alloys.