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Title: Characterization of Al-Mg Alloy Aged at Low Temperatures

Abstract

For this research, long-term aged [343 K (70 °C) for 30 months and natural exposure for over 10 years] Al 5456 H116 samples were characterized using electron backscatter diffraction (EBSD), scanning transmission electron microscopy (STEM), state-of-the-art energy-dispersive X-ray spectroscopy (EDS) systems, and small-angle neutron scattering (SANS). ASTM G-67 mass loss tests of the sensitized Al 5456 alloy samples were conducted. Intragranular Mg-rich precipitates, such as Guinier–Preston (GP) zones, were confirmed in Al 5456 H116 aged at 343 K (70 °C) for 30 months, and the volume of these precipitates is 1.39 pct. β' phase is identified at the grain boundary of a navy ship sample, while high-resolution STEM results reveal no intragranular precipitates. Intergranular corrosion (IGC) of Al 5456 was found to be related to the continuity of intergranular precipitates.

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [3];  [4];  [1];  [1]
  1. Univ. of Utah, Salt Lake City, UT (United States). Department of Metallurgical Engineering
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials Division
  4. Naval Sea Systems Command Carderock Division, West Bethesda, MD (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1427711
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science
Additional Journal Information:
Journal Volume: 48; Journal Issue: 4; Journal ID: ISSN 1073-5623
Publisher:
ASM International
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Stress Corrosion Crack; Scanning Transmission Electron Microscopy; H116 Alloy; Scanning Transmission Electron Microscopy Image; Ultrasonic Impact Treatment

Citation Formats

Yi, Gaosong, Cullen, David A., Littrell, Kenneth C., Golumbfskie, William, Sundberg, Erik, and Free, Michael L. Characterization of Al-Mg Alloy Aged at Low Temperatures. United States: N. p., 2017. Web. doi:10.1007/s11661-017-3992-2.
Yi, Gaosong, Cullen, David A., Littrell, Kenneth C., Golumbfskie, William, Sundberg, Erik, & Free, Michael L. Characterization of Al-Mg Alloy Aged at Low Temperatures. United States. doi:10.1007/s11661-017-3992-2.
Yi, Gaosong, Cullen, David A., Littrell, Kenneth C., Golumbfskie, William, Sundberg, Erik, and Free, Michael L. Mon . "Characterization of Al-Mg Alloy Aged at Low Temperatures". United States. doi:10.1007/s11661-017-3992-2. https://www.osti.gov/servlets/purl/1427711.
@article{osti_1427711,
title = {Characterization of Al-Mg Alloy Aged at Low Temperatures},
author = {Yi, Gaosong and Cullen, David A. and Littrell, Kenneth C. and Golumbfskie, William and Sundberg, Erik and Free, Michael L.},
abstractNote = {For this research, long-term aged [343 K (70 °C) for 30 months and natural exposure for over 10 years] Al 5456 H116 samples were characterized using electron backscatter diffraction (EBSD), scanning transmission electron microscopy (STEM), state-of-the-art energy-dispersive X-ray spectroscopy (EDS) systems, and small-angle neutron scattering (SANS). ASTM G-67 mass loss tests of the sensitized Al 5456 alloy samples were conducted. Intragranular Mg-rich precipitates, such as Guinier–Preston (GP) zones, were confirmed in Al 5456 H116 aged at 343 K (70 °C) for 30 months, and the volume of these precipitates is 1.39 pct. β' phase is identified at the grain boundary of a navy ship sample, while high-resolution STEM results reveal no intragranular precipitates. Intergranular corrosion (IGC) of Al 5456 was found to be related to the continuity of intergranular precipitates.},
doi = {10.1007/s11661-017-3992-2},
journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
number = 4,
volume = 48,
place = {United States},
year = {Mon Feb 06 00:00:00 EST 2017},
month = {Mon Feb 06 00:00:00 EST 2017}
}

Journal Article:
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  • A study has been made of the thermal stability of the [Sigma] phase in Al-Cu-Mg-Ag alloys aged at high temperature (200 to 350 C). This phase, which precipitates as thin plates on the [111][sub [alpha]] planes, has been shown to be replaced by the equilibrium precipitate [theta] (Al[sub 2]Cu) after prolonged aging (e.g. 2,400 h at 250 C). Measurements have been made of the thickening behavior of the [Omega] plates and the various orientations and morphologies of the [theta] phase have been characterized. While there is some evidence for the direct allotropic transformation of [Omega] to [theta], it is concludedmore » that a gradual dissolution/re-precipitation mechanism dominates the changes to microstructure at these high temperatures. Although magnesium and silver are known to segregate to the [Omega] phase, they were not detected in association with [theta]. Rather they were found to partition to sites of the S phase (Al[sub 2]CuMg) which forms as a minor precipitates under these aging conditions.« less
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