Comparison of Notch-Stress with Strain-Controlled Low Cycle Fatigue of Alpha-Beta Titanium Alloys.

Abstract

Prior studies of the present authors provided two different tests of low cycle fatigue endurance of the same set of titanium alloys. Strain controlled push-pull deformation of axial specimens covered crack initiation life of up to 1000 cycles. Notch stress controlled tensile load cycling extended the range to 1 million cycles. All of Ti-6Al-4V, the test materials varied in oxygen content and in effective grain size. The results could not be compared directly because of the disparity in the controlling variables; strain and stress excursions respectively. It is found that both kinds of data form a consistent set if the total stress excursion is used as a basis of comparison, except for cases of overly high notch loading. The earlier strain-controlled results were modeled by a cumulative cyclic creep strain criterion for crack initiation. This criterion appears to embrace also the notch stress results, thus providing a promising means for extrapolating fatigue data. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Dec 04, 1981
Accession Number
ADA108548

Entities

People

  • George R. Yoder
  • J. M. Krafft

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Creep
  • Data Sets
  • Fatigue Tests (Mechanics)
  • Grain Size
  • Hardening
  • Heat Treatment
  • Materials
  • Mechanical Properties
  • Plastic Flow
  • Strain Hardening
  • Stress Concentration
  • Stress Strain Relations
  • Stresses
  • Tensile Stress
  • Test Methods
  • Titanium
  • Titanium Alloys

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Mechanical Engineering/Mechanics of Materials.
  • Regression Analysis.