A Modified Method to Estimate Fatigue Parameters of Wrought Aluminum Alloys

Several methods for estimating fatigue properties of wrought aluminum alloys from simple tensile data or hardness were discussed. Among them, Park-Song’s modified Mitchell’s method provided the best estimation results in low fatigue life regime. Roessle-Fatemi’s hardness method tends to be very erroneous in the present estimations. None of the investigated methods provide the satisfactory estimation results in the case of N _f > 3 × 10⁴ cycles. Besides, correlation between ultimate tensile strength and Brinell hardness was developed. Then, the modified Mitchell’s method utilizing the ultimate tensile strength predicted from Brinell hardness was proposed in this study and successfully applied to estimate fatigue properties for wrought aluminum alloys. This simple method requires only Brinell hardness and modulus of elasticity as inputs, both of which are either commonly available or easily measurable. Prediction capability of this method was evaluated for wrought aluminum alloys with hardness between 120 and 157 HB. Results show that the proposed method provides the best life predictions for wrought aluminum alloys.