Atomic-scale quasi in-situ TEM observation on the redistribution of alloying element Cu in a B4C/Al composite at the initial stage of corrosion. (September 2020)

• Record Type: Journal Article
• Authors: Zhou, Y.T.; Zan, Y.N.; Wang, Q.Z.; Xiao, B.L.; Ma, Z.Y.; Ma, X.L.
• Is Part Of: Corrosion science. Volume 174(2020)
• Publication Date: 2020-09
• Subjects: A. Metal matrix composites -- A. Aluminium -- B. TEM -- C. De-alloying -- C. Pitting corrosion -- C. Segregation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2020.108808
• Languages: English
• ISSNs: 0010-938X

Abstract

Graphical abstract: Highlights: Cu/Mg enrichment was found at the interphase boundary in a B4 C/Al composite. Atomic scale quasi in-situ TEM revealed the dealloying of the Mg/Cu- rich layer. Decomposition of the Mg(Al)B2 promoted the liberation of Cu remnant and pitting of the matrix. Dissolved Cu ions were then redeposited upon the cathodic phases, i.e. B4 C and Mg(Al)B2 . Abstract: The present study reports an atomic level quasi in-situ TEM observation of the redistribution of alloying element Cu in the corrosion process of a B4 C-reinforced Al-Mg-Si-Cu composite. Cu atoms were found to combine with Mg and form a thin layer at the interfaces between the aluminum matrix and nano-reinforcements (i.e. Mg(Al)B2 and Al3 BC). Dealloying of the Cu/Mg-rich layer was revealed. The following decomposition of Mg(Al)B2 resulted in narrow corrosion trenches forming around Mg(Al)B2 and then the localized pitting of the matrix. In addition, the liberated Cu ions were then redeposited and formed noble Cu nano-particles upon cathodic Mg(Al)B2 and B4 C particles.