Journal
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
Volume 41, Issue -, Pages 127-138Publisher
JOURNAL MATER SCI TECHNOL
DOI: 10.1016/j.jmst.2019.11.001
Keywords
Al-Mg-Si alloys; Precipitation; Dislocation; Age-hardening; Electron microscopy
Funding
- National Key Research and Development Program of China [2016YFB0300801]
- National Natural Science Foundation of China [51831004, 11427806,51671082, 51471067]
Ask authors/readers for more resources
In the slightly deformed Al-Mg-Si alloys, dislocation-induced precipitates are frequently observed, and they usually line up, forming sophisticated precipitation microstructures. Using atomic-resolution electron microscopy in association with hardness measurements, we systematically investigated these precipitates in relation to the age-hardening responses of the alloys. Our study reveals that the majority of dislocation-induced complex precipitates are actually short-range ordered while long-range disordered polycrystalline precipitates and multiphase composite precipitates, including polycrystalline U2 precipitates, B'/U2, B'-2/U2, B'/B'-2/U2 and beta'/U2 composite precipitates. It is suggested that the formation of these complex precipitates is mainly owing to a high nucleation rate and rapid growth of different precipitate phases parallel to the associated dislocation lines. Since dislocation-induced precipitates consume more Mg than Si from the matrix and have a high formation kinetics, they will have different impacts on the matrix precipitation in different types of Al-Mg-Si alloys. Our results further demonstrate that for the normally-beta ''-hardened alloy, their formation leads to a coarser precipitate microstructure in the matrix, whereas for the normally-beta'-hardened alloy, their formation reverses the precipitation pathway in the matrix, resulting in a reduced age-hardening potential of the former alloy and an improved age-hardening potential of the latter alloy. (C) 2019 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available