Molybdenum element Mo improves the mechanical properties of the alloy at high temperatures due to the solid solution
hardening. Similar to the Chrome element, higher percentage of Mo could affect the forging capabilities of the material. Titanium
element Ti used for precipitation of c0 phase should not also exceed 1% of the composition in order to provide the optimum
tensile and creep properties. It was also shown that increasing the mass fraction of the Niobium Nb, as essential
element of the d (Ni3Nb) phase, improves the hardness and the yield strength of the material [16].
Fu et al. [17] works state that optimum mechanical properties of the alloy 718 are with a chemical composition including
1% of aluminum, 1% of titan and 5.5% of Niobium.
Based on the above specified requirements, the chemical composition of the fractured blade will be compared with the
ASTM B637 tolerances and the recommended studies’ thresholds which aim to ensure the optimum blade mechanical
characteristics.