Development of fine-grained structure and the mechanical properties of nickel-based Superalloy 718

Hwa-Teng Lee, Wen Hsin Hou

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Grain refinement is the essential concern in producing Superalloy 718 components. Thermomechanical process as a means of producing fine grain structure has attracted significant attention. However, hot forging with deviations on forging temperature results in significant changes in the microstructure. High volume fractions of δ phase thus produced reduce the amount of niobium available for γ' formation and consequently lower the strength. In this work, the combination of heavy plastic deformation with subsequent recrystallization was utilized as an effective method to achieve a fine-grained structure. Specimens in this process were first solution treated at high temperatures and then followed by plastic deformation. Subsequent recrystallization caused an immediate precipitation of a fine, uniformly dispersed δ phase from the niobium oversaturated matrix that prohibited grain growth. A fine-grained structure with grain sizes <1. μm was obtained, smaller than 2.9. μm that has ever been reported in literature. Tensile test results demonstrate a significant improvement in strength and ductility tested at temperatures of 25. °C and 650. °C, respectively.

Original languageEnglish
Pages (from-to)13-20
Number of pages8
JournalMaterials Science and Engineering A
Publication statusPublished - 2012 Oct 15

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


Dive into the research topics of 'Development of fine-grained structure and the mechanical properties of nickel-based Superalloy 718'. Together they form a unique fingerprint.

Cite this