Precipitation process along dislocations in Al-Cu-Mg alloy during artificial aging

▶ HRTEM observations was carried out on the microstructure evolution along dislocations during the aging process. ▶ The precipitation sequence of the S phase at dislocation is suggested to be SSS → GPB zones → S (Type I) → S (Type I) + S (Type II). ▶ Two probable formation modes for Type II S precipitate, namely independently nucleation and growth and lateral growth, were proposed.