Experimental and calculated phases in two as-cast and annealed Mg-Zn-Y alloys
- McGill University, Department of Materials Engineering, Montreal, QC, H3A 2B2 (Canada)
- CANMET-Materials Technology Laboratory, Ottawa, Ontario, K1A 0G1 (Canada)
The CALPHAD (Calculation of Phase Diagram) method was used to select ternary alloys from Mg-Zn-Y system, aimed at determining the role of precipitates in the microstructure and texture evolution of Mg during and after deformation. The selected alloys are Mg-6Zn-1.2Y and Mg-5Zn-2Y. The constituent phases in the as-cast Mg-6Zn-1.2Y alloy are {alpha}-Mg solid solution phase and I (Mg{sub 3}YZn{sub 6}) intermetallic phase. The as-cast Mg-5Zn-2Y alloy is composed of {alpha}-Mg, I and W (Mg{sub 3}Y{sub 2}Zn{sub 3}) phases. The intermetallics in the two alloys form by eutectic reaction, which in Mg-5Zn-2Y alloy results in initially W-phase formation and ultimately I-phase formation during solidification. After heat treatment, the Mg-6Zn-1.2Y and Mg-5Zn-2Y alloys contain nearly the same amount of ternary intermetallics (I and W phases, respectively) in equilibrium with {alpha}-Mg solid solution phase. The main solute in {alpha}-Mg phase is Zn with the same amount in the two alloys. The type and quantity of the phases obtained experimentally disagree with the results obtained from the thermodynamic database. One important discrepancy is that, in Mg-6Zn-1.2Y alloy, the I phase is not stable at the temperature of 430 Degree-Sign C, and that the W phase is the stable phase at this temperature. The differences in the experimental and calculated data indicate that the Mg-Zn-Y system requires to be reassessed with more experimental data. - Highlights: Black-Right-Pointing-Pointer Mg-6Zn-1.2Y and Mg-5Zn-2Y alloys were selected by FactSage Trade-Mark-Sign Thermodynamic software. Black-Right-Pointing-Pointer The I and W intermetallics in the two alloys form by eutectic reaction. Black-Right-Pointing-Pointer The alloys contain similar amounts of different intermetallics in equilibrium with {alpha}-Mg. Black-Right-Pointing-Pointer In Mg-6Zn-1.2Y, the I phase is not stable at the temperature of 430 Degree-Sign C. Black-Right-Pointing-Pointer The hardness of W phase is determined to be lower than that of I phase.
- OSTI ID:
- 22066402
- Journal Information:
- Materials Characterization, Vol. 63, Issue Complete; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of high magnetic field on the evolutions of constituent phases in 7085 aluminum alloy during homogenization
Phase relations and structural features in the system Ni-Zn-B