Revisiting the response of microstructure and performance to cold pre-strain and the early aging stage in Al–Zn–Mg–Cu alloy

Abstract

In recent years, extensive research on dynamic precipitation has led to a growing interest in exploring how deformation affects microstructure and mechanical properties. In this study, the response of microstructure and performance to cold pre-strain and the early aging stage in the Al–Zn–Mg–Cu alloy was investigated using a combination of modelling and experimental approaches. A Kampmann-Wagner based numerical framework was developed and applied to the Al–Zn–Mg–Cu alloy. The deformation or quenching induced dislocations and vacancies, their dynamics and acceleration on the diffusivities of solute atoms, and the competition between homogeneous and heterogeneous nucleation were considered in the framework. The effect of the different pre-strain levels (0%–10%) on the evolution of vacancies, dislocations, precipitation kinetics and hardening are given in detail. The results suggest that the acceleration of precipitation kinetics and hardening during the aging process following pre-strain is primarily attributed to the overall increase in diffusivity resulting from deformation-induced dislocations, rather than vacancies. The simulation framework developed in the current work effectively captures the evolution of microstructure and mechanical properties, which has significant practical implications for materials manufacturing.

Keywords

• Vacancies
• Dislocations
• Al–Zn–Mg–Cu alloy
• Kampmann-Wagner numerical model
• Precipitation hardening simulation