Low Cycle Fatigue (LCF) is one of most common mechanisms behind turbine blade failures. The reason is high stress concentration in notch areas. like fir-tree root groves. which can cause cyclic stress beyond the safe threshold. https://www.ealisboa.com/super-find-2009-2014-Dodge-Ram-1500-4pc-Bolt-on-Rivet-Style-Spyder-Fender-Flares-hot-value/