Influence of Ruthenium Element on Intermediate and High Temperature Creep Properties of a Nickel-base Superalloy

摘要

In the early development of Ni-base superalloy, the strength of alloy was increased by increasing the amount of γ' precipitate. However, the γ' phase was limited to approximately 65-70% volume fraction to maximize precipitation strength. Recent researches showed that further improvement in the strength can be achieved through solid solution strengthening of the γ matrix, e.g., by adding over 5 wt.% Re element. However, if the Re element was excessive, it tended to promote the formation of deleterious topological closed-packed (TCP) phases at the long-term elevated temperatures exposures, resulting in a decrease in the creep properties. In this study, alloys based on Ni-10Co-10W-8.4Cr-5.5Al-5Re-3Ta-1.3Hf-1Ti-0.7Mo-Q.14C alloy which was contained 5 wt.% Re. and various Ru elements were added to base alloy. The purpose of this investigation was to determine the influence of Ru on the intermediate temperature - high stress (760℃/724MPa) and high temperature - low stress (982℃/200MPa) creep properties of alloy. The results showed that the addition of 3 wt.% Ru significantly prevented the formation of TCP phase and prolonged the creep life of alloy.