On the statistical distribution of primary and secondary dendrite arm spacing in cast metals

Statistical distributions of dendrite arm spacing have not been addressed in the literature. Two histograms for primary dendrite arm spacing in a cast nickel-based superalloy, and four histograms from a chill cast 5182 aluminium alloy ingots for secondary dendrite arm spacing have been analysed. For all datasets, lognormal distribution provided excellent fits to the data. Moreover, the Lifshitz–Slyozov–Wagner distribution was found to have systematic error in the fits to the secondary arm spacing data.