HIP effect on the high-temperature creep behavior of a solution-treated nickel-based single crystal superalloy

Micropores and residual eutectics are detrimental to the creep behavior of the nickel-based single crystal (SX) superalloys. The decrease of residual eutectics and micropores in the interdendritic regions by hot isostatic pressing (HIP) can improve the creep rupture life of nickel-based SX superalloy. In this work, the influence of HIP temperature and pressure on the creep rupture life as well as the impact of HIP treatment on creep behavior of nickel-based SX superalloy with solution-treated state at 980 °C/250 MPa were studied. The results show that the improvement of creep rupture life was primarily due to the prolongation of the slow-accelerating creep stage. Increasing HIP temperature from 1280 °C to 1300 °C can raise the creep rupture lives of the HIP-treated samples. During creep, the micropores inside the non-HIP sample increased continuously, whereas that of the HIP-treated sample had little change until creep rupture. The HIP-treated sample had relatively weak plastic deformation in the interdendritic regions compared with the non-HIP sample, suppressing the microcrack initiation and propagation at the end of creep. This study is beneficial for developing a method to improve the creep performance of nickel-based SX superalloys at high temperatures.