Automatic restraint and visual detection of fatigue crack growth by applying an alumina paste

Ichihiko Takahashi, Michio Ushijima, Chiori Takahashi, Susumu Uematsu, Noriyuki Kotani

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4 Citations (Scopus)

Abstract

A paste comprising fine alumina particles was applied on surfaces of steel plate specimens and welded joint specimens, and the effects of the paste on restraint and visual detection of fatigue crack growth were experimentally investigated by performing fatigue tests with in situ observations by a CCD microscope and through various kinds of fractographic observations and elemental analyses using a SEM (Scanning Electron Microscope) and an EPMA (Electron Probe Microanalyser). As a result, the crack growth rate in the plate specimen was drastically retarded by the wedge effect of the alumina particles, and 344% increase in failure life was produced. Similar crack growth restraint effects were also observed on the welded joint specimens, producing 117-175% increase in failure life. In the fatigue tests of the specimens on which the alumina paste was applied, remarkable black color developed in the white alumina paste along the paths of crack propagation, exceedingly facilitating the visual detection of the cracks. An analysis using an X-ray diffractometer showed that the black matter in the paste consists of fine debris derived from the base metal and the alumina particles.

Original languageEnglish
Pages (from-to)531-541
Number of pages11
JournalYosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society
Volume22
Issue number4
DOIs
Publication statusPublished - 2004 Nov

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Keywords

  • Alumina paste
  • COD
  • Fatigue crack growth
  • Fractographic analysis
  • Retardation
  • Stress intensity factor
  • Visual detection
  • Wedge effect
  • Welded joint

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces, Coatings and Films
  • Metals and Alloys

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