### Abstract

Fatigue crack growth (FCG) behavior of magnesium alloys at room temperature (20°C-55%RH) was investigated. Center cracked plate tension (CCT) specimens were used in the FCG tests for applying both tension-compression and tension-tension loading. The effects of R ratio and crack closure on fatigue crack growth behavior of extruded AZ61 and AZ91D magnesium alloys were investigated. From the results, it is found that stress ratio influences the threshold value ΔK_{th} for the materials used. The threshold value decreased with increasing stress ratio. The relationship between fatigue crack growth rate da/dN and stress intensity factor range Δ K for AZ61 was almost identical to that for AZ91D. The effective stress intensity factor range ΔK_{eff} values for R=-1, 0.1 and 0.5 were significantly low compared to Δ K values in the near-threshold region while the difference became smaller as the stress intensity factor range increased. This can be explained by the effect of crack closure, which is more pronounce in the near-threshold region. The effect of R ratio was diminished and all the growth curves laid on the same curve when the fatigue crack growth rate plotted as a function of ΔK_{eff}.

Original language | English |
---|---|

Pages (from-to) | 81-86 |

Number of pages | 6 |

Journal | Materials Science Forum |

Volume | 419-422 |

Issue number | I |

Publication status | Published - 2003 |

Externally published | Yes |

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### Keywords

- Crack closure
- Effective Stress Intensity Factor
- Fatigue Crack Growth
- Magnesium Alloys
- Stress Ratio

### ASJC Scopus subject areas

- Materials Science(all)

### Cite this

*Materials Science Forum*,

*419-422*(I), 81-86.

**Effect of stress ratio on fatigue crack growth behavior of magnesium alloys.** / Sajuri, Zainuddin; Miyashita, Y.; Mutoh, Y.

Research output: Contribution to journal › Article

*Materials Science Forum*, vol. 419-422, no. I, pp. 81-86.

}

TY - JOUR

T1 - Effect of stress ratio on fatigue crack growth behavior of magnesium alloys

AU - Sajuri, Zainuddin

AU - Miyashita, Y.

AU - Mutoh, Y.

PY - 2003

Y1 - 2003

N2 - Fatigue crack growth (FCG) behavior of magnesium alloys at room temperature (20°C-55%RH) was investigated. Center cracked plate tension (CCT) specimens were used in the FCG tests for applying both tension-compression and tension-tension loading. The effects of R ratio and crack closure on fatigue crack growth behavior of extruded AZ61 and AZ91D magnesium alloys were investigated. From the results, it is found that stress ratio influences the threshold value ΔKth for the materials used. The threshold value decreased with increasing stress ratio. The relationship between fatigue crack growth rate da/dN and stress intensity factor range Δ K for AZ61 was almost identical to that for AZ91D. The effective stress intensity factor range ΔKeff values for R=-1, 0.1 and 0.5 were significantly low compared to Δ K values in the near-threshold region while the difference became smaller as the stress intensity factor range increased. This can be explained by the effect of crack closure, which is more pronounce in the near-threshold region. The effect of R ratio was diminished and all the growth curves laid on the same curve when the fatigue crack growth rate plotted as a function of ΔKeff.

AB - Fatigue crack growth (FCG) behavior of magnesium alloys at room temperature (20°C-55%RH) was investigated. Center cracked plate tension (CCT) specimens were used in the FCG tests for applying both tension-compression and tension-tension loading. The effects of R ratio and crack closure on fatigue crack growth behavior of extruded AZ61 and AZ91D magnesium alloys were investigated. From the results, it is found that stress ratio influences the threshold value ΔKth for the materials used. The threshold value decreased with increasing stress ratio. The relationship between fatigue crack growth rate da/dN and stress intensity factor range Δ K for AZ61 was almost identical to that for AZ91D. The effective stress intensity factor range ΔKeff values for R=-1, 0.1 and 0.5 were significantly low compared to Δ K values in the near-threshold region while the difference became smaller as the stress intensity factor range increased. This can be explained by the effect of crack closure, which is more pronounce in the near-threshold region. The effect of R ratio was diminished and all the growth curves laid on the same curve when the fatigue crack growth rate plotted as a function of ΔKeff.

KW - Crack closure

KW - Effective Stress Intensity Factor

KW - Fatigue Crack Growth

KW - Magnesium Alloys

KW - Stress Ratio

UR - http://www.scopus.com/inward/record.url?scp=0037247211&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037247211&partnerID=8YFLogxK

M3 - Article

VL - 419-422

SP - 81

EP - 86

JO - Materials Science Forum

JF - Materials Science Forum

SN - 0255-5476

IS - I

ER -