Skip to main content
placeholder image

Investigation on γ′ stability in CoNi-based superalloys during long-term aging at 900 °C

Journal Article


Abstract


  • γ′-strengthened CoNi-based superalloys containing Ti and Ta are studied to investigate the γ′ stability after long-term aging at 900 °C. Both thermodynamic predictions and experimental observations suggest that there is no formation of CoAl or Co3W phases, indicating that the γ′ phase remains stable in the investigated CoNi-based superalloys. Typical γ/γ′ structure with a relatively high amount of γ′ phase remains in the microstructures of explored CoNi-based superalloys containing Ti and Ta after aging for 3000 h. The secondary MC carbides separate out from γ matrix during aging and different orientation relationships between MC and matrix exist for the explored CoNi-based superalloys: (100)γ//(100)MC, [001]γ//[001]MC for the alloy with Ti; (111¯)γ//(1¯11¯)MC, [011]γ//[011]MC for the alloy with Ta. Nanoindentation was performed to evaluate the mechanical properties of individual γ channel and γ′ precipitate. It is found that indentation modulus of γ′ phase in the explored CoNi-based superalloys locate between those of Ni3Al and Co3(Al, W) alloys, and Ta exhibits stronger strengthening effects as compared to that of Ti.

Publication Date


  • 2020

Citation


  • Guan, Y., Liu, Y., Ma, Z., Li, H., & Yu, H. (2020). Investigation on γ′ stability in CoNi-based superalloys during long-term aging at 900 °C. Journal of Alloys and Compounds, 842. doi:10.1016/j.jallcom.2020.155891

Scopus Eid


  • 2-s2.0-85086328799

Web Of Science Accession Number


Volume


  • 842

Abstract


  • γ′-strengthened CoNi-based superalloys containing Ti and Ta are studied to investigate the γ′ stability after long-term aging at 900 °C. Both thermodynamic predictions and experimental observations suggest that there is no formation of CoAl or Co3W phases, indicating that the γ′ phase remains stable in the investigated CoNi-based superalloys. Typical γ/γ′ structure with a relatively high amount of γ′ phase remains in the microstructures of explored CoNi-based superalloys containing Ti and Ta after aging for 3000 h. The secondary MC carbides separate out from γ matrix during aging and different orientation relationships between MC and matrix exist for the explored CoNi-based superalloys: (100)γ//(100)MC, [001]γ//[001]MC for the alloy with Ti; (111¯)γ//(1¯11¯)MC, [011]γ//[011]MC for the alloy with Ta. Nanoindentation was performed to evaluate the mechanical properties of individual γ channel and γ′ precipitate. It is found that indentation modulus of γ′ phase in the explored CoNi-based superalloys locate between those of Ni3Al and Co3(Al, W) alloys, and Ta exhibits stronger strengthening effects as compared to that of Ti.

Publication Date


  • 2020

Citation


  • Guan, Y., Liu, Y., Ma, Z., Li, H., & Yu, H. (2020). Investigation on γ′ stability in CoNi-based superalloys during long-term aging at 900 °C. Journal of Alloys and Compounds, 842. doi:10.1016/j.jallcom.2020.155891

Scopus Eid


  • 2-s2.0-85086328799

Web Of Science Accession Number


Volume


  • 842