Microstructure dependence of fatigue crack propagation behavior in wrought magnesium alloy

Autor: S. Morita, S. Fujiwara, T. Hori, N. Hattori, H. Somekawa, T. Mayama
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Frattura ed Integrità Strutturale, Vol 10, Iss 35, Pp 82-87 (2016)
Druh dokumentu: article
ISSN: 1971-8993
DOI: 10.3221/IGF-ESIS.35.10
Popis: This paper deals with the fatigue crack propagation behavior of rolled AZ31B magnesium alloy (grain size: approximately 40 m). Fatigue crack propagation tests were performed on single edge notched tension specimens at a stress ratio of R = 0.1 and a frequency of 10 Hz at room temperature. Loading axes were parallel to the rolling direction; fatigue cracks propagated parallel to the transverse direction (L-T specimen), parallel to the short transverse direction (L-S specimen). Loading axis was perpendicular to the rolling direction; fatigue cracks propagated parallel to the transverse direction (S-T specimen). The crack growth rate (da/dN) of the L-S specimen was several times lower than that of the L-T specimen in the examined stress intensity factor range (K). Fracture surfaces of the L-T and L-S specimens showed many steps parallel and perpendicular, respectively, to the macroscopic crack growth direction. The da/dN of the S-T specimen was higher than that of the L-T and L-S specimens in the examined K. The fracture surface was covered by quasi-cleavage facets independent of macroscopic crack growth direction, and the fracture surface roughness at low K was larger than that at high K.
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