Defect size dependence on threshold stress intensity for high-strength steel with internal hydrogen

Y. Murakami, H. Matsunaga, A. Abyazi, Y. Fukushima

研究成果: Contribution to journalArticle査読

13 被引用数 (Scopus)


A series of tensile tests were carried out using hydrogen-precharged specimens of SAE52100. Two types of tensile specimens were used: (i) smooth specimens and (ii) specimens having various shapes of artificial defects with sizes of about 35-500 μm. In the smooth specimens, fracture origins were non-metallic inclusions with the size of 10-30 μm (e.g. Al2O 3™(CaO)x, TiN and TiC). In both types of specimens, hydrogen charging drastically decreased the tensile strength. The fracture toughness determined for the small defects at the fracture origin, that is, the threshold stress intensity KTH calculated from the defect size area and the applied tensile stress at the failure of the specimen σf, showed a defect size dependence, where area denotes the area of the domain defined by projecting the defect on a plane normal to the cylindrical axis of the specimen. Namely, the threshold value was reduced with a decrease in the defect size, which is similar to the crack size dependence in the ΔKth for small fatigue crack. The values of KTH for both the non-metallic inclusions and artificial defects were much smaller than those for large cracks measured by the standard WOL (Wedge Opening Load) and CT (Compact Tension) specimens.

ジャーナルFatigue and Fracture of Engineering Materials and Structures
出版ステータス出版済み - 9 2013

All Science Journal Classification (ASJC) codes

  • 材料科学(全般)
  • 材料力学
  • 機械工学


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