Formulation of initial artificial age-hardening response in an Al-Mg-Si alloy based on the cluster classification using a high-detection-efficiency atom probe

Cluster classification according to the composition based on the atomic density inside clusters in an Al-Mg-Si alloy is originally suggested using a high-detection-efficiency atom probe. The high detection efficiency is better capable for detection of clusters and has a major impact on measured number densities. It is shown that Si-rich clusters with Mg/(Mg+Si) value below 0.4 have smaller atomic density inside clusters, suggesting high vacancy concentration inside the Si-rich clusters. It is revealed that the initial artificial age-hardening response related to the transition behavior from a cluster to the beta" phase at 443 K after aging with various conditions can be determined by the relative volume fractions of the Si-rich clusters and Mg-Si clusters. The relative proportion of the Si-rich clusters can be estimated from the initial artificial age-hardening response in various Al-Mg-Si alloys using the proposed formula. (C) 2017 Elsevier B.V. All rights reserved.