The characterization of dislocation–nanocluster interactions in Al–Mg–Si(–Cu/Ag) alloys

Abstract

The quantification of the interaction between nanoclusters and dislocation motion has received relatively little experimental or theoretical research. In this work, the relationship between nanoclusters and dislocations was investigated by conducting tensile tests at different temperatures for a variety of nanoclusters in Al–Mg–Si alloys. Further, the nanoclusters were characterized by 3D atom probe. The normalized energy required for a dislocation to shear through a nanocluster, g_o , was estimated by using the results from the tensile tests and thermal activation theory. It was possible to characterize differences in nanoclusters for different ageing times as well as changes due to the addition of Cu or Ag. Specifically, it was found that the nanoclusters that formed at 293 K could be differentiated from those formed at 393 K, even after correcting for the nanocluster size. Finally, it was found that the addition of small amounts of Cu or Ag fundamentally altered the dislocation–nanocluster interaction.

Keywords:

• nanocluster
• dislocation
• activation energy
• microalloying element
• Al–Mg–Si alloys

Acknowledgements

This work has been supported by Tokyo Institute of Technology Global COE Program, Education and Research Center for Material Innovation, Japan. The authors would gratefully like to acknowledge the financial support of NSERC (Canada) which helped support the local expenses of Dr Serizawa when she visited UBC to conduct the mechanical tests.