A model for co-clusters and their strengthening in Al-Cu-Mg based alloys: a comparison with experimental data

作者：Starink Marco Jan^*

来源：International Journal of Materials Research, 2012, 103(8): 942-947.

DOI：10.3139/146.110797

• Co-clusters
• Hardening
• Dimer
• Entropy
• Solvus

A model for the thermodynamics of and strengthening due to Cu-Mg co-clusters in Al-Cu-Mg based alloys is analysed and tested. The formulation uses a single interaction enthalpy between dissimilar alloying elements (e.g. Cu and Mg atoms in an Al-Cu-Mg based alloy) combined with the configurational entropy. The metastable solvus in Al-Cu-Mg based alloys is calculated. Recently published small angle X-ray scattering experiments, 3-dimensional atom probe and yield strength data on these type of alloys support the model. The small angle X-ray scattering and hardness experiments, as well as calorimetry experiments, are sensitive to the main free energy (or enthalpy) changes, which are dominated by Cu-Mg bonds formed by the dimers and the local electron densities related to these bonds. 3 dimensional atom probe is less sensitive to dimers, and will detect agglomeration of dimers to form larger clusters.

• 出版日期2012-8