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Title: XRD Technique: A way to disseminate structural changes in iron-based amorphous materials

Abstract

Prevention of corrosion is a vital goal for the Department of Defense when billions of dollars are spent every year. Corrosion resistant materials have applications in all sort of military vehicles, and more importantly in naval vessels and submarines which come in contact with the seawater. It is known that corrosion resistance property can be improved by the used of structurally designed materials in the amorphous state where the atoms are arranged in a non-periodic fashion and specific atoms, tailored to the required properties can be interjected into the matrix for specific application. The XRD techniques reported here is to demonstrate the optimal conditions for characterization of these materials. The samples, which normally contain different compositions of Fe, Cr, B, Mo, Y, Mn, Si and W, are in the form of powders, ribbons and coatings. These results will be compared for the different forms of the sample which appears to correlate to the cooling rate during sample processing. In most cases, the materials are amorphous or amorphous with very small amount of crystallinity. In the ribbon samples for different compositions we observed that the materials are essentially amorphous. In most cases, starting from an amorphous powder sample, the coatings aremore » also observed to be amorphous with a small amount of iron oxide on the surface, probably due to exposure to air.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1046796
Report Number(s):
UCRL-CONF-231250
TRN: US201215%%536
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Presented at: Materials Science & Technology 2007 Conf & Exhibition, Detroit, MI, United States, Sep 16 - Sep 20, 2007
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AIR; AMORPHOUS STATE; ATOMS; COATINGS; CORROSION; CORROSION RESISTANCE; DOLLARS; IRON OXIDES; PROCESSING; SEAWATER; SUBMARINES; US DOD; X-RAY DIFFRACTION

Citation Formats

Saw, C K, Lian, T, Day, D, and Farmer, J. XRD Technique: A way to disseminate structural changes in iron-based amorphous materials. United States: N. p., 2007. Web.
Saw, C K, Lian, T, Day, D, & Farmer, J. XRD Technique: A way to disseminate structural changes in iron-based amorphous materials. United States.
Saw, C K, Lian, T, Day, D, and Farmer, J. Thu . "XRD Technique: A way to disseminate structural changes in iron-based amorphous materials". United States. doi:. https://www.osti.gov/servlets/purl/1046796.
@article{osti_1046796,
title = {XRD Technique: A way to disseminate structural changes in iron-based amorphous materials},
author = {Saw, C K and Lian, T and Day, D and Farmer, J},
abstractNote = {Prevention of corrosion is a vital goal for the Department of Defense when billions of dollars are spent every year. Corrosion resistant materials have applications in all sort of military vehicles, and more importantly in naval vessels and submarines which come in contact with the seawater. It is known that corrosion resistance property can be improved by the used of structurally designed materials in the amorphous state where the atoms are arranged in a non-periodic fashion and specific atoms, tailored to the required properties can be interjected into the matrix for specific application. The XRD techniques reported here is to demonstrate the optimal conditions for characterization of these materials. The samples, which normally contain different compositions of Fe, Cr, B, Mo, Y, Mn, Si and W, are in the form of powders, ribbons and coatings. These results will be compared for the different forms of the sample which appears to correlate to the cooling rate during sample processing. In most cases, the materials are amorphous or amorphous with very small amount of crystallinity. In the ribbon samples for different compositions we observed that the materials are essentially amorphous. In most cases, starting from an amorphous powder sample, the coatings are also observed to be amorphous with a small amount of iron oxide on the surface, probably due to exposure to air.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu May 24 00:00:00 EDT 2007},
month = {Thu May 24 00:00:00 EDT 2007}
}

Conference:
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  • Prevention of corrosion is a vital goal for the Department of Defense when billions of dollars are spent every year. Corrosion resistant materials have applications in all sort of military vehicles, and more importantly in naval vessels and submarines which come in contact with the seawater. It is known that corrosion resistance property can be improved by the used of structurally designed materials in the amorphous state where the atoms are arranged in a non-periodic fashion and specific atoms, tailored to the required properties can be interjected into the matrix for specific application. The XRD techniques reported here is tomore » demonstrate the optimal conditions for characterization of these materials. The samples, which normally contain different compositions of Fe, Cr, B, Mo, Y, Mn, Si and W, are in the form of powders, ribbons and coatings. These results will be compared for the different forms of the sample which appears to correlate to the cooling rate during sample processing. In most cases, the materials are amorphous or amorphous with very small amount of crystallinity. In the ribbon samples for different compositions we observed that the materials are essentially amorphous. In most cases, starting from an amorphous powder sample, the coatings are also observed to be amorphous with a small amount of iron oxide on the surface, probably due to exposure to air.« less
  • We report the first study of the effect of high-energy mechanical deformation on amorphous iron-based metallic alloys. The structural changes happening in amorphous iron-based materials containing Co or Ni during mechanical deformation show that the structural stability of an amorphous alloy against a thermal and a mechanical process are not related. Therefore, the concept of a high local effective temperature during the milling process cannot be singled out as the only reason for the observed structural transformations.
  • Metallic amorphous alloys or metallic glasses have been studied extensively for the last three decades due to their unique characteristics, including superior mechanical properties and corrosion resistance. Iron-based amorphous alloys have in general better corrosion resistance than their polycrystalline cousins such as the austenitic 18-8 stainless steel series (e.g. 316L SS). Fe-based amorphous alloys have even higher localized corrosion resistance than the nickel-based Alloy 22 under many laboratory tested conditions. Electrochemical laboratory tests have shown that when polycrystalline alloys such as Alloy 22 are anodically polarized in hot concentrated chloride brines, they dissolve unevenly following patterns associated with their crystallinemore » character. However, amorphous alloys, when polarized to even higher potentials than the polycrystalline alloys, they dissolve in a desirable uniform manner. This is because the amorphous Fe-based alloys do not offer defects in the metal that can be preferentially attacked. Comparative studies will also be presented on the dissolution modes of Ni-gadolinium and borated stainless steels.« less
  • An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced asmore » melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional stainless steel and nickel-based materials, and are proving to have excellent wear properties, sufficient to warrant their use in earth excavation, drilling and tunnel boring applications. Large areas have been successfully coated with these materials, with thicknesses of approximately one centimeter. The observed corrosion resistance may enable applications of importance in industries such as: oil and gas production, refining, nuclear power generation, shipping, and others.« less