Quality control of AlSi10Mg produced by SLM: Metallography versus CT scans for critical defect size assessment

Defects in Electron Beam Melted Ti-6Al-4V: Fatigue Life Prediction Using Experimental Data and Extreme Value Statistics

“…In Figure 9 a, some indication of two separate defect populations can be seen (solid and dashed lines) in Build A. Romano et al [ 26 ] made similar observations when combining the size measurements of LOF defects and pores into a single distribution. They separated the two defect types based on sphericity criteria since it is not advised to assess the effect of different defect types with a single distribution [ 35 ].…”

“…They evaluated the tails of the defect size distributions with extreme value statistics and assumed random locations of defects. Both the position and size were measured mainly with non-destructive X-ray computed tomography, but also with classic metallography, and the results showed the accurate prediction of fatigue strength [ 14 , 25 , 26 ]. For a broader overview of the effects of defects on fatigue performance, including different modeling approaches, readers are referred to the review article by Sanaei and Fatemi [ 27 ].…”

“…XCT also becomes less effective for high-density materials due to increased X-ray attenuation [ 34 ]. Compared to metallography, XCT is more costly to run, but compensates for that by being less time consuming and more efficient for larger material volumes [ 26 ]. Increased use of the XCT technique has also given rise to a shift in the method of choice for statistical analysis of life-determining defects.…”

Effect of hot isostatic pressing on the critical defect size distribution in AlSi7Mg0.6 alloy obtained by selective laser melting

“…This latter phenomenon can be accounted for in the prediction of the size distribution of the critical defects by restricting the aforementioned volume V to a sub-volume corresponding to the subsurface portion of the loaded part. The application of such a procedure, which assumes that the critical defect is the largest defect found in the subsurface portion of the part, has provided satisfying results for the AlSi10Mg alloy produced by SLM [24].…”

Investigation of the sensitivity of the fatigue resistance to defect position in aluminium alloys obtained by Selective laser melting using artificial defects

“…Indeed, the volume inspected with tomography (V 0 = 855 mm 3 ) was greater than the subsurface portion of the fatigue specimens where critical fatigue cracks are likely to initiate (V = 13 mm 3 ), which can be approximated by multiplying the outer surface of the gauge section by a constant depth corresponding to the average critical defect size. Note that in a general manner, the defect size distribution from CT scan data can be extrapolated accounting for volume effects to predict the size distribution of the critical defects [28]. However, a proper prediction of this distribution would require a larger CT scan volume than the one inspected in this study.…”