Relationship between Defect Size and Fatigue Life Distributions in Al-7 Pct Si-Mg Alloy Castings

Tiryakioğlu, Murat

doi:10.1007/s11661-009-9847-8

Cited by 44 publications

(16 citation statements)

References 46 publications

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“…It worth noting that Figure a shows that there is excellent correlation between fatigue life and the area of the crack initiating particle. This is consistent with other studies that show good correlation between fatigue life and the area of the fatigue crack initiation defect . Furthermore, an example of a large fatal fatigue crack initiating particle (Al 9 FeNi) in this alloy (loaded as shown in Figure a) can be seen in Figure b (≈3114 μm 2 ; L max ≈ 170 μm; N f = 561 010 cycles).…”

Section: Results and Analysissupporting

confidence: 91%

Application of X‐Ray Microtomography to Evaluate Complex Microstructure and Predict the Lower Bound Fatigue Potential of Cast Al–7(0.7)Si–4Cu–3Ni–Mg Alloys

et al. 2017

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The 3D architecture of intermetallics and porosity in two multicomponent cast Al-7(0.7)Si-4Cu-3Ni-Mg alloys is characterized using conventional microscopy and X-ray microtomography. The two alloys are found to contain intermetallic phases such as that have complex networked morphology in 3D. The results also show that HIPping does not significantly affect the volume fraction, size, and shape distribution of the intermetallic phases in both alloys. A novel technique similar to serial sectioning that circumvents quantification difficulties associated with interconnected particles is used to quantify the intermetallics. The largest particle size distribution is then correlated to fatigue performance using extreme value analysis to predict the maximum particle size in a sample of S-N fatigue specimens and subsequently, the lower bound fatigue life. The predictions are found to correlate well with fatigue data. The effect of HIPping on porosity characteristics is also characterized. Large pore clusters with complex morphology are observed in the unHIPped versions of both alloys, but more significant in the low Si (Al-0.7Si-4Cu-3Ni-Mg) alloy. However, these are significantly reduced after HIPping. The differences between 2D and 3D pore morphology and size distribution is discussed in terms of the appropriate pore size parameter for fatigue life prediction.

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Section: Results and Analysissupporting

confidence: 91%

Application of X‐Ray Microtomography to Evaluate Complex Microstructure and Predict the Lower Bound Fatigue Potential of Cast Al–7(0.7)Si–4Cu–3Ni–Mg Alloys

et al. 2017

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“…Furthermore, P (d eq ) equals the cumulative distribution function of the Generalized Extreme Value distribution depending on the equivalent circle diameter d eq , the location µ, the scale σ and the shape parameter ξ. Furthermore, it was shown that the fatigue strength in the finite life region can be assessed by linking the cumulative probability density of fracture-initiating defect size distribution with the Paris-Erdoǧan equation for stable crack growth [18]. Due to the fact that the focus of this work is the fatigue strength assessment of Al-Si cast materials in the long-life fatigue region, Murakami's √ area concept is used, see [19].…”

Section: Introductionmentioning

confidence: 99%

Application of a area -Approach for Fatigue Assessment of Cast Aluminum Alloys at Elevated Temperature

Aigner

Garb

Leitner

et al. 2018

Metals

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This paper contributes to the effect of elevated temperature on the fatigue strength of common aluminum cast alloys EN AC-46200 and EN AC-45500. The examination covers both static as well as cyclic fatigue investigations to study the damage mechanism of the as-cast and post-heat-treated alloys. The investigated fracture surfaces suggest a change in crack origin at elevated temperature of 150 ∘ C. At room temperature, most fatigue tests reveal shrinkage-based micro pores as their crack initiation, whereas large slipping areas occur at elevated temperature. Finally, a modified a r e a -based fatigue strength model for elevated temperatures is proposed. The original a r e a model was developed by Murakami and uses the square root of the projected area of fatigue fracture-initiating defects to correlate with the fatigue strength at room temperature. The adopted concept reveals a proper fit for the fatigue assessment of cast Al-Si materials at elevated temperatures; in detail, the slope of the original model according to Murakami should be decreased at higher temperatures as the spatial extent of casting imperfections becomes less dominant at elevated temperatures. This goes along with the increased long crack threshold at higher operating temperature conditions.

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“…Davidson et al [ 17 ] showed that there is a linear relationship between logarithms of fatigue life and largest defect size in Al-7%Si-Mg alloy castings. Moreover, one of the authors [ 18 , 19 ] demonstrated that the fatigue life distribution can be directly linked to the size distribution of largest defects in Al-7%Si-Mg alloy castings.…”

Section: Introductionmentioning

confidence: 99%

Walker Parameter for Mean Stress Correction in Fatigue Testing of Al-7%Si-Mg Alloy Castings

Özdeş

Tiryakioğlu

2017

Materials

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In this study, performance of two existing Walker parameter estimation models has been investigated. Results show that those developed mainly for steel did not provide reasonable fits to experimental Walker parameters for fatigue data for Al-7%Si-Mg alloy castings in the literature. A strong relationship between the Walker parameter and the structural quality, quantified by the quality index, QT, was observed and an empirical equation to estimate the Walker parameter for these alloys was developed. These findings indicate that the Walker parameter is not an intrinsic material property and the structural quality of the specimens must be taken into account for mean stress correction in fatigue testing.

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Relationship between Defect Size and Fatigue Life Distributions in Al-7 Pct Si-Mg Alloy Castings

Cited by 44 publications

References 46 publications

Application of X‐Ray Microtomography to Evaluate Complex Microstructure and Predict the Lower Bound Fatigue Potential of Cast Al–7(0.7)Si–4Cu–3Ni–Mg Alloys

Application of X‐Ray Microtomography to Evaluate Complex Microstructure and Predict the Lower Bound Fatigue Potential of Cast Al–7(0.7)Si–4Cu–3Ni–Mg Alloys

Application of a area -Approach for Fatigue Assessment of Cast Aluminum Alloys at Elevated Temperature

Walker Parameter for Mean Stress Correction in Fatigue Testing of Al-7%Si-Mg Alloy Castings

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