A Model Ni–Al–Mo Superalloy Studied by Ultraviolet Pulsed-Laser-Assisted Local-Electrode Atom-Probe Tomography

Abstract

This study investigates the effects of the charge-state ratio of evaporated ions on the accuracy of local-electrode atom-probe (LEAP) tomographic compositional and structural analyses, which employs a picosecond ultraviolet pulsed laser. Experimental results demonstrate that the charge-state ratio is a better indicator of the best atom-probe tomography (APT) experimental conditions compared with laser pulse energy. The thermal tails in the mass spectra decrease significantly, and the mass resolving power (m/Δm) increases by 87.5 and 185.7% at full-width half-maximum and full-width tenth-maximum, respectively, as the laser pulse energy is increased from 5 to 30 pJ/pulse. The measured composition of this alloy depends on the charge-state ratio of the evaporated ions, and the most accurate composition is obtained when Ni2+/Ni+ is in the range of 0.3-20. The γ(f.c.c.)/γ'(L12) interface is quantitatively more diffuse when determined from the measured concentration profiles for higher laser pulse energies. Conclusions of the APT compositional and structural analyses utilizing the same suitable charge-state ratio are more comparable than those collected with the same laser pulse energy.

Three-dimensional nanoscale characterisation of materials by atom probe tomography

“…Relevant APT experimental design is mostly discussed in recent books [24,25,55]. A few papers specifically address issues related to proper selection and evaluation of analysis conditions [56][57][58][59][60][61][62][63], but in general, discussions beyond listing the actual experimental parameters used for a particular study are beyond the scope of a majority of the peer-reviewed literature. We have tried to capture the essential spirit and experimental details contained in the relevant published literature in this section.…”

Atomically resolved calcium phosphate coating on a gold substrate

“…It offers 3-D imaging and chemical composition measurements at the atomic scale (0.1-0.3 nm spatial resolution in depth, 0.3-0.5 nm laterally). [32][33][34] This capability has led to the study of a wide range of materials on the sub-nanometer to nanometer length scale for a broad range of physical problems; for example, studies of alloys and superalloys, 35,36 nanowires, 37 nanoparticles, 38 transistors, 39 powders, 40 and even metallic thin films and electrodeposits. [41][42][43][44] APT has also been utilized for studying biomineralization.…”