Effect of artificial aging time on torsional fatigue life and cyclic behavior of AA6351 aluminum alloy and evaluation of estimation methods

Abstract The effects of artificial‐aging time on monotonic properties and torsional fatigue of AA6351 aluminum alloy were studied in this paper. Fatigue tests were carried out by the strain‐controlled condition. Monotonic and cyclic torsional behavior, fatigue life, and estimation methods were verified. Results showed the distance between monotonic and cyclic curves progressively decreased as aging time increased from 1 to 2 and 6 h at 170°C. The yield strength values were subsequently 74.5, 110.7, and 142.5 MPa for monotonic torsion and 127, 145, and 160 MPa for cyclic torsion test (half‐life). Alloy in all aging times showed similar fatigue life in high cycle (N f > 10 5 cycles), and time 1 h, longer fatigue life in low cycle (N f < 10 4 cycles). All specimens presented cyclic hardening at strain amplitudes ranges tested. The estimation methods showed good prediction for the fatigue parameters.