The Influence of Prolonged Natural Aging on the Subsequent Artificial Aging Response of the AA6111 Automotive Alloy

摘要

The influence of prolonged ambient temperature storage on the subsequent precipitation behavior of the AA6111-T4P automotive alloy during artificial aging has been investigated using hardness testing and high-resolution transmission electron microscopy. The results indicate that growth of atomic co-clusters and GP zones during ambient storage suppress the onset of Q' and Q precipitation, and retard the formation of elemental silicon particles. However, the overall hardening response of the stored AA6111 T4P alloy to subsequent peak-aging and over-aging treatments is not altered by the significant reduction in the volume fraction of Q' and Q precipitates due to their lower strengthening effects compared with GP zones and the QaEuro(3) phase precipitates.