Comparison of Fatigue Life of AA2050-T852 and AA7050-T7452 Alloy Forgings at Different Orientations

Abstract

This study compares the fatigue performance between the AA2050-T852 alloy and AA7050-T7452 alloy traditionally used in aircraft structures. Rotating beam fatigue tests were performed on AA2050-T852 and AA7050-T7452 specimens cut from forged plates with different orientations and at different thickness levels. The samples were tested at 345 MPa (50 ksi), 276 MPa (40 ksi), 207 MPa (30 ksi) and 172 MPa (25 ksi). Scanning Electron Microscope (SEM) images showed mixed mode in all samples. However, the equiaxed dimples were more abundant and finer in the AA2050-T852 alloy. The results indicated that AA2050-T852 alloy demonstrated better fatigue life performance compared to AA7050-T7452 alloy at almost all stresses. No significant difference in fatigue anisotropy was found in one alloy versus the other.