Calculations for three nickel-base superalloys Udimet 700, Inconel 718 and Waspaloy; their detailed compositions can be found in [36,37,34,35,33]. Fig. 5 compares the model and the experimental data using the inputs listed in Table 2. The calculations are represented with the uncertainty range and the reported measurements [36,37,34,35,33] as points. The results are fascinating since the model correctly estimates the Paris slopes, although it marginally overestimates the fatigue behaviour (we have checked that this overestimation is not explained by modulus variations between the different materials). A similar level of agreement was found for titanium Ti-6Al-4V, 7075 aluminium alloy were made and compared against published measurements [38,39], Fig. 6. The model nicely captured the slope for both the titanium and aluminium alloys, and it again slightly overestimates the fatigue crack growth rates.
In order to further test the model a colleague from industry supplied input data (last two columns, Table 2) without revealing the alloy type for the purpose of making blind predictions, for which the crack growth rates would be revealed after the calculations are made. Fig. 7 shows calculations, and the subsequent experimental data on the same Ti6Al4V alloy with two different heat treatments. The agreement obtained is good.