Fatigue in Single Crystal Nickel Superalloys

Abstract

This program investigates the behavior of single crystal airfoil materials. The fatigue initiation processes in single crystal materials are significantly more complicated and involved than fatigue initiation and subsequent behavior of a (single) macrocrack in conventional, isotropic, materials. In cast single crystal nickel alloys, two basic fracture modes, crystallographic and non-crystallographic, are seen in combination. They occur in varying proportions depending upon temperature and stress state. Crystallographic orientation with respect to applied load also affects the proportion of each and influences the specific crystallographic planes and slip directions involved. Mixed mode fracture is observed under monotonic as well as cyclic conditions.

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Document Details

Document Type
Technical Report
Publication Date
Nov 15, 1991
Accession Number
ADA243453

Entities

Organizations

  • Pratt & Whitney

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Alloys
  • Contracts
  • Crystals
  • Fracture (Mechanics)
  • Grain Boundaries
  • Heat Treatment
  • Materials
  • Mechanics
  • Nickel
  • Nickel Alloys
  • Nickel Aluminide
  • Orientation (Direction)
  • Probability
  • Program Management
  • Propulsion Systems
  • Single Crystals
  • Space Propulsion

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Powder metallurgy of Titanium alloys.