The fatigue properties of 6061-T6 aluminum (Al) alloy containing additional solute magnesium (Mg) is studied. As previously reported, this special alloy exhibits eminent strain-aging characteristics which is absent in a normal 6061-T6 alloy with a stoichiometric Mg 2 Si composition. In this study, particular attention is paid to the environmental effect on the fatigue properties of this new alloy. The S-N curves of the alloys are compared in different environments (ambient air, dry air, dry nitrogen). A clear knee-point (fatigue limit), which is atypical to the normal 6061-T6 alloy, appears for the new alloy irrespective of the environment. The fatigue limit is shown to be controlled by the threshold against small crack propagation in all environments. On the other hand, the coaxing effect, the manifestation of a time-dependent strengthening mechanism at the non-propagating crack tip, is clearly observed in the ambient air.
All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Mechanics of Materials
- Civil and Structural Engineering
- Materials Science(all)