High temperature strength of fine-grained, particle-dispersed V–(1.7–2.4)wt%Y alloys with different grain sizes and particle densities

In order to examine the high temperature strength of fine-grained, particle-dispersed V–Y alloys as a function of grain size and dispersed particle density, three V–(1.7–2.4)Y (in wt%) alloys were prepared by mechanical alloying and hot isostatic pressing. The alloys had grain sizes of 270–500 nm, particle size of around 15 nm and particle densities of (1.3–7.2) × 1021 m−3. The alloys, together with V–4Cr–4Ti (NIFS-Heat1), were annealed and tensile tested at room and high temperatures from 873 to 1273 K. At room temperature and up to around 1073 K, V–(1.7–2.4)Y alloys exhibited higher strengths than V–4Cr–4Ti, with strength increasing with decreasing grain size and increasing particle density. Above 1173 K, however, V–(1.7–2.4)Y alloys showed lower strengths than V–4Cr–4Ti. These results are due to a strong temperature dependence of strengths of V–(1.7–2.4)Y above 923 K compared with that of V–4Cr–4Ti. The observed mechanical behavior of V–(1.7–2.4)Y is discussed from the viewpoint of the deformation controlling mechanism.