High temperature deformation of V-1.6Y-8.5W-(0.08, 0.15)C alloys

In order to improve the high temperature strength of fine-grained and particle-dispersed V alloys, V-1.6Y-8.5W-0.08C and V-1.6Y-8.5W-0.15C (wt%) were fabricated by mechanical alloying and hot isostatic pressing, followed by annealing at 1000 and 1200 °C for 3.6 ks. Dispersoids of Y2O3, V2C, WC and W2C are detected by X-ray diffraction in the 1000 and 1200 °C-annealed specimens. Tungsten dissolves in the V matrix after annealing at 1200 °C. Tensile tests were performed at temperatures from 800 to 1100 °C at initial strain rates from 1.0 × 10−4 to 1.0 × 10−2 s−1. The yield stress at 900 °C of 1200 °C-annealed V-1.6Y-8.5W-0.15C is approximately 2 times as high as that of V-4Cr-4Ti, due to combination of solution hardening by W and dispersion hardening by the dispersoids. The obtained stress exponent of plastic strain rate and activation energy for deformation suggest that the deformation of V-1.6Y-8.5W-0.08C and V-1.6Y-8.5W-0.15C is controlled by solute atmosphere dragging.