1966 年 15 巻 154 号 p. 512-516
A study has been made of the aging behavior of Al-3.5% Cu Alloy through X-ray and metallographic observations and hardness test when aged at the temperature 175∼200°C under cyclic loads. When the plastic region is subjected to aging process under the cyclic loads the degree of age hardening is greater than that of ordinary aging and fine precipitates are observed in the cyclic loaded portion. The time required to attain maximum hardness is far shorter than that for ordinary aging. But if the strain rate exceeds a certain amount and fatigue effect become predominant, further age hardening will be inhibited.
The aging of elastic or slightly plastic deformation under cyclic loads accelerates the relief of internal strain.
From these results it is concluded that the diffusion rate of solute atoms depend on the cyclic strain rate, and that the degree of age hardening is much more remarkable when precipitation takes place in the region of laminar slip under the cyclic load.