Influence of defect morphology and position on the fatigue limit of cast Al alloy: 3D characterization by X-ray microtomography of natural and artificial defects

Effects of artificial and natural defects on fatigue strength of a cast aluminum alloy

“…The threshold stress intensity value range of cast Al was reported between 0.98 and 1.80 MPa m 0.5 . 13 According to the calculated data, this value is closer to the more favorable upper limit, which is, due to the smaller number of material discontinuity, proving the benefits of the VPDC method. On the other hand, the KT approach is proved to be a correct method to indirectly determine the ΔK th value of a material compared to a standardized test for stable crack propagation.…”

“…The geometric factor of the internal defect was α int = 0.5, while for the surface defect, it was α surf = 0.65. 13 The KT diagram represents the influence of the defect size on the fatigue strength at a given number of cycles. This relation is represented in a log-log diagram, where the defect size and the given fatigue limit (fatigue strength) are shown at a given number of cycles (Figure 3A).…”

“…The slope of the monotonically decreasing part is constant; its value is À0.25. 13 In this data cloud, the ffiffiffiffiffiffiffiffiffi area p and σ amp value pairs were measured, and the threshold stress intensity range value (ΔK th ) was varied to fit the monotonically decreasing curve section according to Equation (3).…”

The investigation of artificial and natural defects on the fatigue strength of vacuum-assisted high pressure die cast AlSi9Cu3(Fe) aluminum alloy

“…According to this evaluation method the calculated ΔK th value was found to be 1.8 MPa m 0.5 , this threshold stress intensity is an acceptable value, and it is in accordance with the literature. Based on the literature data, the threshold stress intensity value range of cast aluminum was reported between 0.98 and 1.80 MPa m 0.5 [35,36,37]. According to the calculated data, this value is closer to the more favorable upper limit, which is due to the smaller number of material discontinuity, proving the benefits of the VPDC method.…”

Effect of spherical inclusions on fatigue anisotropy of HSLA-100 steel

“…Comprehensive studies have been done by resear chers about the fatigue behaviour of specimens containing artificial defects of different characteristics such as sizes, area percent and so on. It is quite proven that the effective size, distance from surface and quantity (as defined by their area percent) of inclusions affect the fatigue behaviour of steels [40][41][42]. There is an inverse relationship between fatigue life with area percent and effective size of inclusions within a given cross-sectional area [43,44].…”