Effect of ti content on the microstructure and high-temperature creep property of cast fe-ni-based alloys with high-al content

Gokul Obulan Subramanian, Changheui Jang, Ji Ho Shin, Chaewon Jeong

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
3 Downloads (Pure)

Abstract

The cast Fe-Ni-based austenitic heat-resistant alloys with 4.5 wt% Al and varying Ti content were developed for high-temperature application. With increase in Ti content, strength of model alloys increased gradually at 700C and 750C. At 750C, alloys with 35Ni–(2~4)Ti composition showed a significant increase in creep rupture life compared to 30Ni–1Ti alloy, attributed to the increase in γ’-Ni3 (Al,Ti) precipitates due to higher Ni and Ti content. Among the 35Ni–(2~4)Ti alloys, increasing Ti content from 2 to 4 wt% gradually increased the creep rupture life in the as-cast condition. The creep rupture life was improved after solution annealing treatment, however, the beneficial effect of higher Ti content was not evident for 35Ni–(2~4)Ti alloys. After solution annealing, interdendritic phases were partially dissolved, but coarse B2-NiAl phases were formed. The size and amount of coarse B2-NiAl phases increased with Ti content. In the creep-tested specimens, creep void nucleation and crack propagation were observed along the coarse B2-NiAl phases, especially for high-Ti alloys. Therefore, the beneficial effect of the increase in γ’-Ni3 (Al,Ti) precipitates for high-Ti alloys on creep property was limited due to the detrimental effect of the presence of coarse B2-NiAl phases.

Original languageEnglish
Article number82
Number of pages16
JournalMaterials
Volume14
Issue number1
Early online date26 Dec 2020
DOIs
Publication statusPublished - Jan 2021

Bibliographical note

Funding Information:
This research was funded by National Research Foundation (NRF) of Rep. of Korea as the Nuclear R&D Program, grant numbers 2020M2A8A402393721 and 2019M2D2A2050927. The APC was funded by National Research Foundation of Rep. of Korea.

Keywords

  • Alumina-forming alloys
  • B2-NiAl phase
  • Creep
  • Heat resistant alloys
  • γ’-Ni (Al,Ti) precipitates

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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