Article ID Journal Published Year Pages File Type
7171393 International Journal of Fatigue 2018 31 Pages PDF
Abstract
This work aims to quantify the effect of natural shrinkages on the fatigue limit of A357-T6 cast aluminum alloy. The main objective is to characterize the fatigue strength of the alloy following the ASTM X-ray standard defect identification, by correlating a different ASTM indication to a fatigue limit reduction. The analysis has been conducted on six customized castings with two defect types (cavity and sponge shrinkages) and a different harmfulness ASTM grade as defined by Non Destructive Testing (NDT) standard. The effect of the defect size has been correlated with the ASTM grade and a Kitagawa-Takahashi diagram has been generated for surface defects. A micro Computed-Tomography (μ-CT) analysis has been performed in order to compare the defect size estimation using two equivalent parameters AREA1/2 and VOLUME1/3. A Defect Stress Gradient (DSG) approach has been proposed to simulate the Kitagawa-Diagram obtained for surface defects. Finally, the effect of the specimen surface has been investigated for the reference material (ASTM grade < 1) by comparing the “as cast” surface to a machined surface finish.
Related Topics
Physical Sciences and Engineering Engineering Mechanical Engineering
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