Constitutive Model of Triple-Step-Aged Al–Mg–Si Alloy Incorporating Precipitation Kinetics

In the present study, we present a constitutive model for predicting tensile behavior by considering the characteristics of individual precipitates occurring during a single- or triple-step aging treatment of Al–Mg–Si alloy. The solution treatment was conducted at 550 °C for 1 h and then quenched in water to reach room temperature. Different aging treatments were carried out: at 170 °C for 8 h and 210 °C for 4 h for single-step aging and at 140 °C for 80 min, 170 °C for 80 min, and 200 °C for 80 min for triple-step aging. The triple-step aging process resulted in excellent strength, even though a shorter processing time was required than for conventional single-step aging. This was due to the effects of precipitation strengthening and dispersion strengthening related to the various aging precipitates. In particular, it was verified that the calculated yield strength could be significantly varied according to the types and characteristics of each precipitation phase.