The Effects of Thermal Treatments on the Material Damping and Fatigue Properties of 2024 Aluminum Alloy

摘要

A comparison is made of the fatigue life and internal damping of 2024 aluminum alloy, naturally aged and artifically aged. The naturally aged alloy exhibited the higher damping and longer fatigue life when tested at resonant conditions. The naturally aged material showed longer fatigue life at stresses above 16300 psi when tested in reversed bending. The only significant metallurgical difference observed was the increased vacancy concentration in the naturally aged alloy. Resonant fatigue tests conducted in vacuum environments resulted in greatly increased fatigue lives, compared with ambient conditions. It is postulated that moisture accelerates crack propagation in fatigue failures. (Author)