ALCHEMI of L12-Ordered Ni76Al21Hf3and gamma prime particles-Reference-Cited by-同舟云学术

ALCHEMI of L12-Ordered Ni76Al21Hf3and gamma prime particles

Published:1996-08-11 Issue: Volume:54 Page:552-553
ISSN:0424-8201
Container-title:Proceedings, annual meeting, Electron Microscopy Society of America
language:en
Short-container-title:Proc. annu. meet. Electron Microsc. Soc. Am.

Author:

Bentley J.,Anderson Ian M.

Abstract

Recent improvements to the atom location by channeling-enhanced microanalysis (ALCHEMI) technique now allow reliable measurements of site distributions in ordered alloys. Early zone-axis ALCHEMI of Ll2-ordered Ni3Al-based alloys was plagued by ionization delocalization; for Ni76Al21Hf3at <001> the fraction of Hf on the Al sublattice, pHf ‘Al’, = −127%. Reanalysis by statistical ALCHEMI was no better, giving pHf ‘AT’ = −220 ± 190%, contrary to the claims that delocalization effects should be minimized. The same data set analyzed with the reformulated ALCHEMI method yields pHf ‘Al’, = 80 ± 25%.Further experiments have been performed at ∼140K in a Philips CM12 operated at 120 kV and equipped with an EDAX 9900 spectrometer and superUTW Si(Li) detector. The diffracting conditions were carefully adjusted with the beam (not specimen) tilt, a probe size of ∼200 nm and beam divergence of ∼3 mrad were used, and the current in the probe was monitored and held constant at ∼1 nA.

Publisher

Cambridge University Press (CUP)

Subject

General Medicine

Reference10 articles.

1. Research at the Oak Ridge National Laboratory (ORNL) SHaRE User Facility sponsored by the Division of Materials Sciences, U.S. Department of Energy, under contract DE-AC05-960R22464 with Lockheed Martin Energy Research Corp., and by an appointment (IMA) to the ORNL Postdoctoral Research Associates Program, which is administered jointly by the Oak Ridge Institute for Science and Education and ORNL. The authors thank Drs. E.L. Hall (GE Corp. R&D) and J.A. Horton, Jr. (ORNL) for providing specimens.

2. Anderson, I. M. and Bentley, J. , these proceedings.

3. Alloying behaviour of Ni3Al, Ni3Ga, Ni3Si and Ni3Ge

4. Anderson, I. M. , these proceedings.

5. Anderson, I.M. and J. Bentley, these proceedings.