On the size distribution of fracture-initiating defects in Al- and Mg-alloy castings

The use of defect size distributions in models for fatigue life is reviewed. A brief summary of extreme value statistics is provided. The analysis of data reported in the literature on the size of fracture-initiating defects in Al- and Mg-alloy castings by using the general extreme value distribution is discussed. Results provide strong evidence that the size of defects on fracture surfaces of cast Al- and Mg-alloys follows the Gumbel distribution. The indications of these results are discussed in the paper.