Remarkable near-surface microstructure of nanoparticles and oxide film in laser shock peened Al-Zn-Mg-Cu alloy. (September 2021)

• Record Type: Journal Article
• Authors: Sharma, Anurag; Song, Jie; Furfari, Domenico; Mannava, Seetha R; Vasudevan, Vijay K
• Is Part Of: Scripta materialia. Number 202(2021)
• Publication Date: 2021-09
• Subjects: Laser shock peening without coating (LSPwC) -- Al-Zn-Mg-Cu (7075-T6) alloy -- Nanoparticles (NPs), Oxide film: Scanning/transmission electron microscopy (S/TEM); Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2021.114012
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The near-surface microstructure in an Al-Zn-Mg-Cu (7075-T6) alloy after Laser Shock Peening without Coating (LSPwC) was characterized by advanced electron microscopy methods. A remarkable microstructure composed of a ~2 μm wide newly solidified matrix recast surface layer embedded with O-rich Al nanoparticles (NPs) with the close-packed orientation relationship (OR) as the surrounding Al matrix has been discovered, together with a nano-scale aluminum oxide layer formed on the outermost surface. The formation mechanism is associated with high-pressure surface ablation leading to melting, vaporization and shock-assisted rapid solidification during the LSPwC process. The close-packed OR between NPs and matrix is believed to be due to surface energy minimization. Graphical abstract: Image, graphical abstract