Tensile Flow Behavior of 9Cr–2WVTa Reduced-Activation Ferritic/Martensitic Steel

Tensile flow behavior of 9Cr–2WVTa ferritic/martensitic (RAFM) steel in normalized-tempered condition has been studied based on Voce equation over the temperature range of 25–600 °C. Yield strength (YS) and ultimate tensile strength (UTS) decrease with increase in temperature. However, the elongation decreases with increase in temperature up to 400 °C and then increases beyond 400 °C. True stress–true plastic strain curves at all temperatures are adequately described by the Voce equation. While saturation stress (σ_s) decreases with temperature, the rate at which the stress approaches the saturation value (n_V) increases with temperature. The variation of the stress increment up to saturation stress (σ_un) with temperature shows a plateau in the temperature range of 200–400 °C. Moreover, the product of σ_un and n_V (σ_un·n_V) is inversely proportional to the elongation. The relation of elongation to σ_un·n_V can be described by a power law with the exponent of −1.63.