Plastic Strain Localization in Superalloy Single Crystals.

Abstract

Single crystals of two Nickel-based superalloys were tested under compression and fatigue conditions. Surface replies were periodically stripped and examined in the TEM. Very fine surface details were observed with slip line spacings on the order of 30 nm observable and by knowing crystal orientation slip lines could be defined as containing as few as 100 dislocations. A distinct difference was observed in the nature of surface slip between the two alloys tested with the high misfit alloy leading to broad slip bands and the low misfit alloy leading to very fine and discrete slip steps. The occurrence of porosity in single crystal superalloys was also studied as a function of crystal growth rate. The volume fraction of porosity was observed to depend on the mode of solidification (i.e. cellular dendritic). Higher growth rates were also found to result in lower volume fractions of porosity.

Document Details

Document Type
Technical Report
Publication Date
May 31, 1985
Accession Number
ADA176817

Entities

People

  • A. F. Giamei
  • D. L. Anton

Organizations

  • United Technologies Corporation

Tags

DTIC Thesaurus Topics

  • Alloys
  • Compression
  • Crystal Growth
  • Crystals
  • Dislocations
  • Orientation (Direction)
  • Porosity
  • Single Crystals
  • Solidification
  • Superalloys

Fields of Study

  • Materials science

Readers

  • Materials Science and Engineering.
  • Powder metallurgy of Titanium alloys.

Technology Areas

  • Space