Materials Science and Metallurgy Engineering
ISSN (Print): 2373-3470 ISSN (Online): 2373-3489 Website: http://www.sciepub.com/journal/msme Editor-in-chief: Apply for this position
Open Access
Journal Browser
Go
Materials Science and Metallurgy Engineering. 2018, 5(1), 1-4
DOI: 10.12691/msme-5-1-1
Open AccessArticle

Precipitation Behavior in an Al-Mg Alloy with High Mg Composition

Takuya Yako1, Koichiro Fukui1, Mao Naito1 and Mahoto Takeda1,

1Department of Materials Engineering, Yokohama National University, Yokohama 240-8501, Japan

Pub. Date: August 26, 2018

Cite this paper:
Takuya Yako, Koichiro Fukui, Mao Naito and Mahoto Takeda. Precipitation Behavior in an Al-Mg Alloy with High Mg Composition. Materials Science and Metallurgy Engineering. 2018; 5(1):1-4. doi: 10.12691/msme-5-1-1

Abstract

We have investigated the precipitation phenomena which occur at high aging temperatures in an Al-Mg alloy with high Mg concentration by means of Vickers hardness (HV) testing, differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and analytical scanning transmission electron microscopy (STEM-EDX). It was found that the hardness and heat changes are closely correlated, and that the size of the exothermic heat peak depends on the quantity of β'- phase formed during isothermal aging prior to the DSC measurements. This implies that the formation of β'-phase precipitates is mainly responsible for the increase in hardness. Our TEM observations showed that β'-phase precipitates are plate-like in morphology and form on matrix {100}planes, whilst stable β-phase precipitates are granular in shape. In-situ TEM using a heating holder revealed that β-phase precipitates grew by consumption of β'-phase platelets. Element-maps obtained by STEM-EDX indicated that the composition of β'-phase platelets was approximately Al-33at%Mg.

Keywords:
aluminum-magnesium alloy precipitation isothermal aging Vickers microhardness differential scanning calorimetry transmission electron microscopy

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

Figures

Figure of 9

References:

[1]  M. Otsuka, R. Horiuchi, “Ductility loss of Al-Mg alloys at high temperatures,“ Japan Institute of Metals, 48 (7), 688-693, 1984.
 
[2]  E.C.W. Perryman and G.B. Brook. “Mechanism of precipitation in aluminum-magnesium alloys“, J. Inst. Metals, 79, 19-34. 1951
 
[3]  M.Kubota, J.F. Nie and B.C.Muddle, “Characterization of precipitation hardening response and as-quenched microstructures in Al-Mg(-Ag) alloys”, Mat. Trans., 45(12), 3256-3263, 2004.
 
[4]  S. Osaki, Y. Kojima, T. Takahashi, “Stress corrosion cracking and intergranular corrosion of 5083 aluminum alloy”, Japan Institute of Light Metals, 25 (5) 173-178, 1975.
 
[5]  T. Takahashi, T. Sato, “Formation of a modulated structure and an ordered structure in concentrated Al-10% and 14%Mg alloys”, Japan Institute of Metals, 50 (2), 133-140, 1986.
 
[6]  K. Osamura and T. Ogura, “Metastable phases in the early stage of precipitation in Al-Mg alloys”, Metall. Trans., 15A (5), 835-842, May. 1984.
 
[7]  T. Sato, Y. Kojima and T. Takahashi, “Modulated structures and GP zones in Al-Mg alloys”, Metall. Trans., 13A (8), 1373-1378, Aug. 1982.
 
[8]  S. Nebti, D. Hamana and G. Cizeron, “Calorimetric study of pre-precipitation and precipitation in Al-Mg alloy”, Acta Metall. Mater., 43 (9), 3583-3588, 1995.
 
[9]  M. J. Starink and A.-M. Zahra, “β' and β precipitation in an Al-Mg alloy studied by DSC and TEM”, Acta Mater., 46(10), 3381-3397, Jun. 1998.
 
[10]  M. J. Starink and A.-M. Zahra, “Precipitation kinetics of an Al-15%Mg alloy studied by microcalorimetry and TEM”, Mater. Sci. Forum, 217-222, 795-800, 1996.
 
[11]  H. Inagaki, “Precipitation of the β-phase in Al-Mg alloys”, Z. Metallkd., 96 (1), 45-53, 2005.
 
[12]  R. Nozato, S. Ishihara, “Calorimetric study of precipitation process in Al-Mg alloys”, Transactions of the Japan Institute of Metals, 21 (9), 580-588, 1980.
 
[13]  K. Fukui, M.Takeda, T.Endo, “Morphology and thermal stability of metastable precipitates formed in an Al-Mg-Si ternary alloy aged at 403K to 483K”, Materials Lett., 59 (11), 1444-1448, 2005.