Influence of porosity and environmental impact on fatigue life of magnesium alloys

Abstract

Based on experimental investigations using specimens with different grades of porosity, a significant influence of the material condition of die-cast magnesium alloys on the accuracy of fatigue-life estimation according to the local-strain approach is verified if the data-base is not related to the microstructure of the component. In order to address this transferability issue, a porosity-depending formulation is proposed. Based on a sensitivity analysis, a simplified, empirical engineering approach has been derived that describes the effect of the inherent porosity on fatigue strength via the fatiguestrength exponent b. Furthermore, it is shown that the degradation of the fatigue-behaviour in chloride-containing media is not simply determined by the external corrosive attack, but also influenced by inner defects competing with the environmental impact.

Fatigue properties of a structural rotor blade adhesive under axial and torsional loading

“…More detailed analyses are required to estimate the individual contribution of the porosity level, tempering, and fiber orientation in terms of material properties and safety factors. However, the porosity level is interpreted as the main reason for the differences in fatigue performance as similar load level‐dependent observations have been made for various metallic alloys with different levels of porosity in literature 36–38 …”

“…However, the porosity level is interpreted as the main reason for the differences in fatigue performance as similar load level-dependent observations have been made for various metallic alloys with different levels of porosity in literature. [36][37][38] Despite the differences in fatigue performance shown in Figure 9, the Stüssi (or Stüssi-Haibach) S-N model fits the data very well. The same was found by Rosemeier and Antoniou 39 and Rosemeier et al 40 for epoxybased resins/adhesives.…”