Modeling the hardness and yield strength evolutions of aluminum alloy with rod/needle-shaped precipitates

For heat-treatable aluminum alloy containing rod/needle-shaped precipitates, a strengthening model for aging hardening behavior has been developed to describe the variations of dimension and volume fraction of the precipitates, and the yield strength and hardness with aging time. The model incorporates both the strengthening mechanisms of dislocation cutting the precipitates at underaged stage and bypassing the precipitates at overaged stage. It has been shown that the model predictions broadly agree with the experimental data for Al–Mg–Si alloys at varied aging time and aging temperatures. Thus, the model can be used to predict the variation of yield strength and hardness with aging time and aging temperature.