title: 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.
authors.affiliation: 1School of Materials Science and Engineering,Southeast University,Jiyin Road,Jiangning District,Nanjing,Jiangsu 211189,China.
authors.forename: Yiyou
authors.initials: Y
authors.lastname: Tu
authors.affiliation: 2Department of Materials Science and Engineering,Northwestern University,2220 Campus Drive,Evanston,IL 60208-3108,USA.
authors.forename: Elizaveta Y
authors.initials: EY
authors.lastname: Plotnikov
authors.affiliation: 2Department of Materials Science and Engineering,Northwestern University,2220 Campus Drive,Evanston,IL 60208-3108,USA.
authors.forename: David N
authors.initials: DN
authors.lastname: Seidman
keywords: mass-resolving power