Abstract
In order to know the effect of cold-working upon the age-hardening, Al-Cu-Mg-Zn alloy was rolled in cold after annealing, quenching or age-hardening and the change in hardness was studied. The hardening during cold-working increases but the hardening by aging after working decreases as the reduction of rolling increases. In process of heating after rolling (upward of reduction about 40%), the slip lines were observed with the microscope from the temperature at which precipitation ocucrred and they grew with rising temperature. It was clear that the minimum interval between two lines was 2∼4 μ and also the slides at cross 2∼5 μ at heigher reduction.
