A New Approach Towards Characterizing Microstructural Influence on Material Behavior Under Very High Cycle

Abstract

Very high cycle fatigue (VHCF), in which components undergo fatigue lifetimes well beyond traditional design limits of 107 cycles, is not well understood and is becoming an increasingly prevalent deformation state in aerospace applications. Components are now designed to handle increasingly long lifetimes (>109cycles), and it is critically important to be able to accurately predict when these components will fail and to intelligently tailor them for improved performance. Toward this end, a new methodology was developed for the small-scale investigation of fatigue crack initiation and growth during VHCF loading, and was used to investigate environmental and microstructural effects on the fatigue lifetimes of the polycrystalline titanium alloy Ti-6242S. Small fatigue crack growth in Ti-6242S, a commonly utilized alloy in aerospace applications, was examined in vacuum and in controlled partial pressures of water vapor, high purity oxygen, and high purity hydrogen.

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 2015
Accession Number
AD1006930

Entities

People

  • Samantha Daly

Organizations

  • University of Michigan

Tags

Communities of Interest

  • Air Platforms
  • Space

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Electron Microscopes
  • Electron Microscopy
  • Electronic Mail
  • Fatigue Life
  • Fatigue Tests (Mechanics)
  • Manufacturing
  • Materials
  • Materials Engineering
  • Materials Science
  • Materials Testing
  • Mechanical Properties
  • Mechanics
  • Microscopy
  • Partial Pressure
  • Scanning Electron Microscopy
  • Students

Fields of Study

  • Materials science

Readers

  • Circadian Sleep-Wake Regulation and Chronobiology
  • Mechanical Engineering/Mechanics of Materials.
  • Systems Analysis and Design

Technology Areas

  • Space