Quantitative evaluation of fatigue life of cast aluminum alloys by non-destructive testing and parameter model

The presence of production-related defects in cast aluminum alloy components leads to reduction in their fatigue strength. The optimal use of their high strength-to-weight benefits is thereby restricted. There are numerous qualitative approaches relating the defects characteristics to fatigue analysis. This work presents a method to quantitatively evaluate the fatigue life of defect-prone cast aluminum alloys. The investigation was carried-out by non-destructive analysis of cast aluminum alloy samples using X-ray computed tomography. The microstructural discontinuities were characterized and quantified in terms of defect size, morphology and distance to specimen surface. These were subsequently used as input in a new parameter model for fatigue life calculation. The results correlate with fatigue experiments and finite-element calculations. This approach provides the possibility to extensively evaluate the fatigue properties of cast aluminum alloy components based on non-destructive test methods. It guarantees an improvement of control mechanisms within the scope of quality assurance.