| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Magnesium Technology 2020
|
| Presentation Title |
Intermetallic Phase Formation in Mg-Ag-Nd (QE) and Mg-Ag-Nd-Zn (QEZ) Alloys |
| Author(s) |
Rainer Schmid-Fetzer, Jian-Feng Nie, Xiaojun Zhao, Houwen Chen |
| On-Site Speaker (Planned) |
Rainer Schmid-Fetzer |
| Abstract Scope |
The intermetallic phase in the solution-treated microstructure of commercial magnesium alloy QE22 (Mg-2.5Ag-2.0Nd-0.7Zr, wt.%) has been investigated using scanning electron microscopy, electron diffraction, atomic-resolution scanning transmission electron microscopy (STEM) and thermodynamic modeling. In contrast to previous reports the orthorhombic structure (space group Cmcm, a = 1.02 nm, b = 1.18 nm, c = 1.00 nm) and a composition of NdAgMg11 are determined. The present experimental data are used to construct a thermodynamic description of the Mg-Ag-Nd system which is embedded in a multicomponent Mg alloy database. Implications on the formation temperature range and thermal stability of this phase and alloy solidification are discussed based on the calculated Mg–Nd–Ag phase diagram and Scheil solidification paths of alloys. The impact of Ag-replacement in such QE alloys by Zn-addition in the Mg-Ag-Nd-Zn (QEZ) alloy system is elaborated using appropriate thermodynamic simulations to reveal the competition with other intermetallics. |
| Proceedings Inclusion? |
Planned: |