Microstructure and properties of Mg-Nd-Zn-Zr alloys

Wang, H. and Ning, Z. L. and Liang, W. Z. and Cao, F. Y. and Sun, J. F. (2010) Microstructure and properties of Mg-Nd-Zn-Zr alloys. In: 2009 International Conference and Exhibition on Materials and AustCeram (MA 2009), 1-3 Jul 2009, Gold Coast, Australia.

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Abstract

One of the limitations of magnesium alloys is their low mechanical properties at elevated temperatures. In order to improve the creep strength, rare earth element neodymium Nd is added to Mg-0.3Zn-0.32Zr alloy. A significant grain refinement has already been achieved by the Zr addition in the base metal. The inclusion of Nd further reduces grain size from 120 μm to 75 μm. When the Nd content is less than 1%, the Nd is fully dissolved into Mg matrix. Increasing the Nd addition to 1.6% leads to a precipitation of Mg 12Nd intermetallic phase at grain boundaries. The Nd-contained materials undergo a T6 heat treatment with a solution treatment at 530°C for 8 hours followed by an aging at 250°C for 12 hours. The heat treatment results in the Nd fully dissolved and then re-precipitated as Mg12Nd, distributing as cluster within the grains and along the grain boundaries. This Mg12Nd precipitation significantly increases the mechanical properties of the materials, especially the high temperature properties. The 200°C tensile strength is 120 MPa for 0.2% Nd-contained alloy and 200 MPa at 2.6% Nd. Even at a higher temperature, 300°C, the Nd-contained alloys still retain significant strength, 60MPa for 0.2% Nd alloy and 110 MPa for 2.6% Nd alloy. The heat treatment also results in some grain coarsening, and Nd acts as effective barriers for the grain agglomeration.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: © Institute of Materials Engineering Australasia Ltd. No evidence of copyright restrictions preventing deposit of Accepted Version.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 07 Mar 2017 04:35
Last Modified: 08 Mar 2017 01:46
Uncontrolled Keywords: creep strengths; elevated temperature; grain coarsening; intermetallic phase; Mg-Nd-Zn-Zr alloys; microstructure and properties; solution treatments; T6 heat treatment
Fields of Research : 03 Chemical Sciences > 0302 Inorganic Chemistry > 030204 Main Group Metal Chemistry
09 Engineering > 0912 Materials Engineering > 091207 Metals and Alloy Materials
09 Engineering > 0915 Interdisciplinary Engineering > 091505 Heat and Mass Transfer Operations
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
URI: http://eprints.usq.edu.au/id/eprint/25755

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