Effect of 2 wt% Ti addition on high-temperature strength of fine-grained, particle dispersed V–Y alloys

In order to examine the effects of 2 wt% Ti addition on microstructures and room-and high-temperature strengths for fine-grained, particle dispersed V–Y alloys, a V–1.7Y–2.1Ti (in wt%) alloy was fabricated by powder metallurgical (P/M) methods. Microstructural examinations were made by transmission electron microscopy (TEM). Tensile tests were performed at temperatures from room-temperature to 1273 K at initial strain rates from 1 × 10−5 to 1 × 10−2 s−1. The results were compared with those of V–(1.7–2.4)Y and V–4Cr–4Ti (NIFS heat-1) alloys. TEM examinations showed that 2.1% Ti addition provides an extended capability of maintaining a fine-grained structure in P/M V–Y alloys with larger inter-particle distance. Tensile test results indicated that the high-temperature yield strength of V–1.7Y–2.1T is considerably higher than expected from the grain-size dependence of the yield strength, and that the deformation controlling mechanism is essentially the same as that for V–1.7Ti. The observed effects of Ti addition are discussed.