Acta Metallurgica Sinica (English Letters) ›› 1990, Vol. 3 ›› Issue (4): 276-281.

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SHORT FATIGUE CRACK BEHAVIOUR IN ISO-STRESS SPECIMENS

HOGN Youshi LU Yonghua ZHENG Zhemin Institute of Mechanics,Academia Sinica,Beijing,China Institute of Mechanics,Academia Sinica,Beijing 100080,China   

  • 收稿日期:1990-08-25 修回日期:1990-08-25 出版日期:1990-08-25 发布日期:2009-10-10

SHORT FATIGUE CRACK BEHAVIOUR IN ISO-STRESS SPECIMENS

HOGN Youshi LU Yonghua ZHENG Zhemin Institute of Mechanics,Academia Sinica,Beijing,China Institute of Mechanics,Academia Sinica,Beijing 100080,China   

  • Received:1990-08-25 Revised:1990-08-25 Online:1990-08-25 Published:2009-10-10

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摘要： <正> Fatigue tests were made on a vibration machine using specially designed specimens to investi-gate the initiation and propagation features of short fatigue cracks in a weld metal.The spec-imens were triangular in shape so that when loaded as a cantilever beam the surface tensilestress is constant.Test results show that short fatigue cracks mainly originate from slip bandswithin ferrite grains.The development of short fatigue cracks is marked by a gradual increasein crack density with fatigue cycles.Coalescence of short cracks leads to crack propagationand the crack path is predominantly transgranular.

Abstract: Fatigue tests were made on a vibration machine using specially designed specimens to investi- gate the initiation and propagation features of short fatigue cracks in a weld metal.The spec- imens were triangular in shape so that when loaded as a cantilever beam the surface tensile stress is constant.Test results show that short fatigue cracks mainly originate from slip bands within ferrite grains.The development of short fatigue cracks is marked by a gradual increase in crack density with fatigue cycles.Coalescence of short cracks leads to crack propagation and the crack path is predominantly transgranular.

Key words: iso—stress specimen, short fatigue crack, weld metal