On the fabrication of atom probe tomography specimens of Al alloys at room temperature using focused ion beam milling with liquid Ga ion source

Mondal, S and Bansal, U and Makineni, SK (2022) On the fabrication of atom probe tomography specimens of Al alloys at room temperature using focused ion beam milling with liquid Ga ion source. In: Microscopy Research and Technique .

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Abstract

In this work, a simple rectangular milling technique was demonstrated to prepare needle shape atom probe tomography (APT) specimens from Al alloys by focused-ion-beam (FIB) milling using Ga+ ions at room temperature. Ga has high miscibility in Al owing to which electropolishing technique is preferred over Ga+ ion FIB instruments for the fabrication of APT specimens. Although, site specific sample preparation is not possible by the electropolishing technique. This led to the motivation to demonstrate a new rectangular milling technique using Ga+ FIB instrument that resulted a significant reduction of Ga+ ion impregnation into the specimens. This is attributed to the reduction of milling time (&lt;30 s at 30 kV acceleration voltage) and the use of lower currents (&lt;0.3Â nA) compared to the conventional annular milling method. The yield of specimens during field evaporation in APT was also significantly increased from around 8 million ions to more than 86 million ions due to the avoidance of Ga+ ion embrittlement. Therefore, the currently demonstrated rectangular milling technique can be used to prepare APT specimens from Al-alloys and obtained accurate compositions of matrix, phases, and hetero-phase interfaces with Ga < 0.1 at%.

Item Type:	Journal Article
Publication:	Microscopy Research and Technique
Publisher:	John Wiley and Sons Inc
Additional Information:	The copyright for this article belongs to the John Wiley and Sons Inc
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	27 May 2022 05:51
Last Modified:	27 May 2022 05:51
URI:	https://eprints.iisc.ac.in/id/eprint/72756

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