4.7 Article

Nano-phase transformation of composite precipitates in multicomponent Al-Mg-Si(-Sc) alloys

Journal

JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
Volume 110, Issue -, Pages 216-226

Publisher

JOURNAL MATER SCI TECHNOL
DOI: 10.1016/j.jmst.2021.09.037

Keywords

Al alloy; Strengthening mechanism; Phase transition; Transmission electron microscopy

Funding

  1. National Natural Sci-ence Foundation of China [52061003, U20A20274, 51661003]
  2. Natural Science Foundation of Guangxi Province [2018GXNSFAA050012]
  3. Science and Technology Major Project of Guangxi [AA17204036-1]
  4. Guangxi Key Laboratory of Processing for Non-ferrous Metallic and Featured Materials [GXYSYF1803]

Ask authors/readers for more resources

This study revealed the microstructural differences between Sc-added and Sc-free Al-Mg-Si-Sc alloys using atomic-scale transmission electron microscopy and atomic-resolution spectroscopy. The addition of Sc atoms not only accelerates the initial stage of hardening but also improves the stability of transitional precipitates, leading to finer and longer precipitate needles. The thermal stability of the alloy is greatly enhanced by the addition of Sc.
Sc-addition can significantly enhance the performance of the micro-alloyed Al-Mg-Si-Sc alloys. However, the mechanisms by which the Sc element modifies the microstructure of the alloys are still unknown in many cases. Here, using atomic-scale transmission electron microscopy and atomic-resolution spectroscopy, we have revealed the microstructural differences between two age-hardened Al-0.5Mg-0.4Si (wt.%) alloys with and without Sc-addition. The first significant effect of Sc-addition on the precipitation microstructure of the Al-Mg-Si-Sc alloy is that Sc-atoms may distribute at the ,B-precipitate/Al-matrix interface and therefore accelerate aging kinetics at the initial stage of hardening. The second significant effect of Sc-addition is that in the transition from the ,B-hardened peak-age stage to the ,B' -hardened late stage, Sc-atoms can greatly improve the stability of transitional ,B/B'/ ,B' composite precipitates by entering the B'-substructures and/or locating at the precipitate/Al interfaces. As such Sc-atoms effectively suppress ,B to ,B' transformation and cross-sectional coarsening of both ,B and composite precipitates, leading to much finer precipitate needles with smaller diameter but much larger length, as compared with those precipitate needles formed in the alloy without Sc-addition. Hence, the alloy with Sc-addition exhibits a much better thermal stability than that without Sc.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available