Examination of focused ion beam-induced damage during platinum deposition in the near-surface region of an aerospace aluminum alloy. (March 2019)

• Record Type: Journal Article
• Authors: Thompson, Adam W.; Harris, Zachary D.; Burns, James T.
• Is Part Of: Micron. Volume 118(2019)
• Page Start: 43
• Page End: 49
• Publication Date: 2019-03
• Subjects: Focused ion beam -- FIB damage -- Aluminum alloys -- TEM -- Deformation; Microscopy -- Periodicals; Electron Probe Microanalysis -- Periodicals; Microscopy -- Periodicals; Microscopie -- Périodiques; Microscopy; Periodicals; 502.82
• DOI: 10.1016/j.micron.2018.12.004
• Languages: English
• ISSNs: 0968-4328

Abstract

Highlights: FIB damage during Pt deposition on Al alloys depends on the Pt deposition protocol. Use of a combined E-beam/I-beam Pt deposition approach reduces observed damage. A minimum E-beam Pt depth of 100 nm is recommended to effectively prevent damage. Abstract: It is well known that damage induced by impinging Ga + ions during focused ion beam (FIB) milling of transmission electron microscopy (TEM) specimens can obfuscate subsequent TEM characterization, especially in the near-surface region of the TEM foil. Numerous strategies for minimizing this damage have been invoked, with the most common being the deposition of a Pt 'strap' at the area of interest. However, damage can still occur in the near-surface region during this Pt deposition step and the variation in the character and extent of this damage with applied Pt deposition parameter, especially in complex structural alloys, is not well characterized. In this study, the damage induced in an aerospace Al alloy (AA7075-T651) during five different Pt deposition protocols is examined using TEM. Results indicate significant variations in damage character and depth amongst the applied Pt deposition protocols, with damage being effectively eliminated using a combined electron-beam/ion-beam Pt deposition strategy. These experimental results are found to be in good agreement with Monte Carlo-based simulations of ion implantation and the implications of these findings on recent experiments in the fracture mechanics community are explored.