Temperature dependence of deformation mechanisms of a new Ni-based superalloy and high-temperature property optimization

The influence of temperature on the deformation mechanisms of a new Ni-based super -alloy named K4800 containing 35 vol% g' were investigated. We studied the temperature dependence of deformation mechanisms and used the alloying method to optimize the high-temperature properties of the alloy. By analyzing slightly deformed microstructures, the dominant deformation mechanisms of alloy K4800 at the yielding stage were identified as: the anti-phase boundary (APB) shearing from RT to 600 degrees C, stacking faults (SFs) shearing and Orowan looping at 600-800 degrees C, and Orowan looping/cross-slip/climbing above 800 degrees C. We found that it was the activation of thermally assisted processes declined the strengthening effect of g' phase and impaired the high-temperature strength of the alloy above 800 degrees C. First-principles calculations were employed to investigate the effects of alloying elements on the formation and stability of stacking faults in K4800 alloy by using a 48-atom Ni3(Al, Ti) orthorhombic supercell. Considering the effectiveness of elements in lowering stacking faults energy, Co and W elements were chosen to alleviate the strength degradation of K4800 alloy above 800 degrees C. The deformation mechanism and properties of these three alloys at elevated temperature were also revealed and discussed.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The influence of temperature on the deformation mechanisms of a new Ni-based superalloy named K4800 was investigated. The study found that temperature has a significant impact on the alloy's deformation mechanisms, and the activation of thermally assisted processes can reduce the strengthening effect of certain phases and impair the high-temperature strength of the alloy. Additionally, alloying elements were used to alleviate the strength degradation at elevated temperatures.