The role of ALCHEMI in understanding the properties of ordered intermetallic alloys
Abstract
After one and one-half decades of development, ALCHEMI is approaching the status of an established analytical technique. Many of the problems that have plagued ALCHEMI, especially for the analysis of ordered intermetallic alloys, are now well understood, and accurate site-distributions can be extracted from a variety of intermetallic alloys. This paper begins with an overview of the factors that can lead to large systematic errors or gross misinterpretations of ALCHEMI data, with illustrations from a variety of ordered intermetallic alloys. The paper concludes with a discussion of ALCHEMI in the broader context of understanding the properties of ordered intermetallic alloys. The results of systematic studies are used to illustrate the role of ALCHEMI in determining the competing effects of thermodynamic and kinetic factors during alloy processing and the correlation of alloy properties with the atomic site distributions on which the properties ultimately depend.
- Authors:
- Publication Date:
- Research Org.:
- Oak Ridge National Lab., Metals and Ceramics Div., TN (United States)
- Sponsoring Org.:
- USDOE Office of Energy Research, Washington, DC (United States)
- OSTI Identifier:
- 290936
- Report Number(s):
- ORNL/CP-98595
ON: DE99000361; BR: KC0201010; TRN: AHC29901%%141
- DOE Contract Number:
- AC05-96OR22464
- Resource Type:
- Technical Report
- Resource Relation:
- Other Information: PBD: [1998]
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; CRYSTAL STRUCTURE; INTERMETALLIC COMPOUNDS; MICROANALYSIS; RELIABILITY; CORRELATIONS; EXPERIMENTAL DATA
Citation Formats
Anderson, I.M.. The role of ALCHEMI in understanding the properties of ordered intermetallic alloys. United States: N. p., 1998.
Web. doi:10.2172/290936.
Anderson, I.M.. The role of ALCHEMI in understanding the properties of ordered intermetallic alloys. United States. doi:10.2172/290936.
Anderson, I.M.. Sun .
"The role of ALCHEMI in understanding the properties of ordered intermetallic alloys". United States.
doi:10.2172/290936. https://www.osti.gov/servlets/purl/290936.
@article{osti_290936,
title = {The role of ALCHEMI in understanding the properties of ordered intermetallic alloys},
author = {Anderson, I.M.},
abstractNote = {After one and one-half decades of development, ALCHEMI is approaching the status of an established analytical technique. Many of the problems that have plagued ALCHEMI, especially for the analysis of ordered intermetallic alloys, are now well understood, and accurate site-distributions can be extracted from a variety of intermetallic alloys. This paper begins with an overview of the factors that can lead to large systematic errors or gross misinterpretations of ALCHEMI data, with illustrations from a variety of ordered intermetallic alloys. The paper concludes with a discussion of ALCHEMI in the broader context of understanding the properties of ordered intermetallic alloys. The results of systematic studies are used to illustrate the role of ALCHEMI in determining the competing effects of thermodynamic and kinetic factors during alloy processing and the correlation of alloy properties with the atomic site distributions on which the properties ultimately depend.},
doi = {10.2172/290936},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Nov 01 00:00:00 EST 1998},
month = {Sun Nov 01 00:00:00 EST 1998}
}
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A detailed understanding of the structure of ordered intermetallic systems is difficult at best, causing a serious disconnect in the typical process-structure-properties approach to alloy development. Basic information, like the site substitution schemes of various alloying elements, partitioning behavior in multiphase alloys, and the dependence of these phenomena with concentration and higher order alloying additions is necessary to predict and understand the effect of various alloying schemes on the physical and mechanical properties of a material. It is only recently that theoretical methods can begin to provide useful insight in these areas, as most current techniques suffer from strong limitationsmore »
-
Practical limitations of ALCHEMI measurements on ordered intermetallic alloys
ALCHEMI determinations of sublattice occupancy in Cu{sub 50}Au{sub 50-x}Pd{sub x} alloys and Ni{sub 3}Al-based alloys containing Fe, Co, and Hf illustrate some practical limitations of the technique. The restrictions imposed by domain size, disordered surface layers, illumination conditions, coherent bremsstrahlung peaks, ionization delocalization effects, and the need for axial rather than planar channeling are discussed. 12 refs., 3 figs. -
(Modeling and experimental efforts on ordered intermetallic alloys)
The travelers spent one week each at ORNL and LANL visiting the groups which are currently involved in the Materials by Design directive of the ECUT Materials Program. The progress made and problems encountered in using the senior traveler's phenomenological structure maps in the search for new cubic, ductile, ordered intermetallics were reviewed. The problems of limited solid solubility and brittleness of certain cubic alloys were noted and a specific trialuminide system identified for future collaborative experimental and theoretical investigation. -
(High-temperature ordered intermetallic alloys)
The traveler was invited to tour through and provide technical guidance for the Japan National Project on High-Temperature Ordered Intermetallic Alloys, which was sponsored by MITI, Japan. The traveler stayed in Japan for three weeks and visited a total of nine research institutes and industrial laboratories active in intermetallic research. During the visit, the traveler learned of the recent research and development of two intermetallic model materials--titanium aluminide (TiAl) and niobium aluminide (Nb{sub 3}Al) selected by MITI. The traveler also gave lectures on recent advances in ordered intermetallic alloys with emphases on brittle fracture and ductility improvement. The MITI's projectmore » -
(Lecture on ordered intermetallic alloys)
The traveler gave a week-long lecture on Ordered Intermetallic Alloys --- Physical Metallurgy, Mechanical Behavior and Alloy Design at the Instituto de Pesquisas Energeticas e Nucleares, National Commission for Nuclear Energy, Brazil. While in Brazil, the traveler learned about recent research on Ni{sub 3}Al alloys and industrial interest in ordered intermetallics.