Figure 2

(a) Stress-life (S-N) fatigue data for the notched MG and the notched UHSS. Data are presented in terms of the reversal cycles to failure, 2N_f, as a function of (a) the applied stress amplitude, σ_a = (σ_max − σ_min)/2, and (b) the applied stress amplitude normalized by the ultimate tensile strength, i.e., σ_a/σ_UTS. The table in (a) lists the values of the fatigue coefficient, , and the fatigue exponent, b, which were obtained by linear fitting.