Applications of atomic-resolution HAADF-STEM and EDS-STEM characterization of light alloys

• Published in: IOP conference series. Materials Science and Engineering Vol. 219; no. 1; pp. 12005 - 12012
• Main Author: Nie, Jian-Feng
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.07.2017
• Subjects: Alloying elements; Aluminum; Chemical precipitation; Electron energy; Electron energy loss spectroscopy; Heat treating; Light metal alloys; Magnesium base alloys; Microalloying; Plates; Precipitates; Scanning transmission electron microscopy; Spectrum analysis; Transmission electron microscopy
• ISSN: 1757-8981; 1757-899X; 1757-899X
• DOI: 10.1088/1757-899X/219/1/012005

Precipitation-hardened aluminium and magnesium alloys often contain a uniform distribution of plate-shaped precipitates of intermediate or equilibrium phases that form on rational planes of the matrix phase. Micro-alloying additions can change the identity and/or distribution of these precipitate plates, but the precise roles of the micro-alloying elements in the formation of such precipitate plates are still a subject of debate. A key reason for this is the lack of direct experimental observation of the details of the distribution/segregation of these elements in and surrounding precipitates from conventional transmission electron microscopy. While the advent of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) provides much more information at the atomic-scale, there is still a need for performing atomic-resolution chemical mapping using advanced STEM techniques, such as energy-dispersive X-ray spectroscopy (EDS-STEM) and/or electron energy-loss spectroscopy (EELS-STEM), if the precise roles of the micro-alloying elements are to be revealed.