The effect of thermomechanical processing on the microstructure and creep behavior of Udimet alloy 188

S. C. Longanbach, C. J. Boehlert

Research output: Chapter in Book/Report/Conference proceedingConference contribution

  • 3 Citations

Abstract

Udimet 188 alloy was subjected to thermomechanical processing in attempt to understand the effects of cold-rolling deformation on the microstructure and tensile-creep behavior. Commercially available sheet was cold rolled to varying amounts of deformation (between 5%-35% reduction in sheet thickness) followed by a solution treatment at 1191°C for one hour followed by air cooling. This sequence was repeated four times to induce a favorable grain boundary character distribution containing a high volume fraction of low-energy grain boundaries. The resultant microstructure was characterized using electron backscattered diffraction. The effect of the thermomechanical processing treatment on the high-temperature (760-815°C) creep behavior was evaluated. Conventional lever-arm creep experiments were performed in an open air environment. The measured creep stress exponents (5.7-6.4) suggested that dislocation creep was dominant at 760°C for stresses ranging between 100-220MPa. The material exhibited a significant extent of grain boundary cracking. The fhermomechanical processing treatments which resulted in the greatest fractions (∼0.8) of special grain boundaries (low-angle boundaries + coincident site lattice boundaries) also exhibited the lowest creep rates. Thus a correlation was exhibited between the grain boundary character distribution and the minimum creep rates. Creep rupture experiments were performed at T=815°C and σ= 165MPa and the thermomechanical processing treatment which resulted in the greatest special boundary fraction also resulted in the greatest average time-to-rupture.

LanguageEnglish (US)
Title of host publicationProceedings of the International Symposium on Superalloys
Pages461-468
Number of pages8
StatePublished - 2008
Event11th International Symposium on Superalloys, Superalloys 2008 - Champion, PA, United States
Duration: Sep 14 2008Sep 18 2008

Other

Other11th International Symposium on Superalloys, Superalloys 2008
CountryUnited States
CityChampion, PA
Period9/14/089/18/08

Profile

Udimet alloys
Creep
grain boundaries
microstructure
Microstructure
Processing
Grain boundaries
tensile creep
air cooling
levers
cold rolling
electron diffraction
exponents
Cold rolling
Air
Electron diffraction
air
Volume fraction

Keywords

  • Cobalt-based alloy
  • Creep
  • Electron backscatter diffraction
  • Microstructure

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Longanbach, S. C., & Boehlert, C. J. (2008). The effect of thermomechanical processing on the microstructure and creep behavior of Udimet alloy 188. In Proceedings of the International Symposium on Superalloys (pp. 461-468)

The effect of thermomechanical processing on the microstructure and creep behavior of Udimet alloy 188. / Longanbach, S. C.; Boehlert, C. J.

Proceedings of the International Symposium on Superalloys. 2008. p. 461-468.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Longanbach, SC & Boehlert, CJ 2008, The effect of thermomechanical processing on the microstructure and creep behavior of Udimet alloy 188. in Proceedings of the International Symposium on Superalloys. pp. 461-468, 11th International Symposium on Superalloys, Superalloys 2008, Champion, PA, United States, 9/14/08.
Longanbach SC, Boehlert CJ. The effect of thermomechanical processing on the microstructure and creep behavior of Udimet alloy 188. In Proceedings of the International Symposium on Superalloys. 2008. p. 461-468.
Longanbach, S. C. ; Boehlert, C. J./ The effect of thermomechanical processing on the microstructure and creep behavior of Udimet alloy 188. Proceedings of the International Symposium on Superalloys. 2008. pp. 461-468
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