Internal Fatigue Failure Mechanism of High Strength Steels in Gigacycle Regime

Abstract:

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Gigacycle fatigue behavior in high-strength steels tested under rotary bending fatigue was summarized in this paper. Characteristic of the very high cycle fatigue is to be caused the transition of fracture mode from surface-induced fracture to subsurface inclusion-induced one. In the vicinity of an inclusion at the origin of internal crack, granular-bright-facet (GBF) area was formed during extremely long fatigue cycles. It was pointed out that the formation of GBF area was an important factor for the control of the internal fatigue fracture in gigacycle regime. The GBF area revealed a very rough granular morphology compared with the area outside the GBF inside the fish-eye zone, and was related to the carbide distribution in the microstructure of the matrix. From the detailed observation of fracture surface and computer simulation by FRASTA method, the GBF area formation mechanism in a gigacycle fatigue regime was proposed as the ‘dispersive decohesion of spherical carbide model’.

Info:

Periodical:

Key Engineering Materials (Volumes 378-379)

Edited by:

Dr. T. S. Srivatsan, FASM, FASME

Pages:

65-80

DOI:

10.4028/www.scientific.net/KEM.378-379.65

Citation:

K. Shiozawa and L. T. Lu, "Internal Fatigue Failure Mechanism of High Strength Steels in Gigacycle Regime", Key Engineering Materials, Vols. 378-379, pp. 65-80, 2008

Online since:

March 2008

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Price:

$35.00

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