Phase equilibria and structural investigations in the system Al-Fe-Si
Martin C J Marker1, Barbara Skolyszewska-Kühberger1, Herta S Effenberger2
1University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Währingerstraße 42, 1090 Wien, Austria.
Intermetallics
|April 19, 2016
Summary
Researchers investigated the Al-Fe-Si system, discovering a new ternary phase and detailing phase compositions. This study refines understanding of the Al-Fe-Si phase diagram and thermodynamic models.
Area of Science:
- Materials Science
- Metallurgy
- Crystallography
Background:
- The Al-Fe-Si system is critical for various industrial applications.
- Accurate phase diagrams are essential for materials development and processing.
Purpose of the Study:
- To experimentally determine phase equilibria in the Al-rich and Fe-rich parts of the Al-Fe-Si system at elevated temperatures.
- To characterize new phases and refine the understanding of existing phase boundaries.
- To validate and improve thermodynamic models for the Al-Fe-Si system.
Main Methods:
- Isothermal and vertical sections of the Al-Fe-Si system were studied.
- Phase characterization using Optical Microscopy, Powder X-ray Diffraction (XRD), Electron Probe Microanalysis (EPMA), and Scanning Electron Microscopy (SEM).
- Thermal analysis using Differential Thermal Analysis (DTA) and comparison with CALPHAD (Calculation of Phase Diagrams) assessments.
Main Results:
- A new ternary high-temperature phase, τ12 (Al48Fe36Si16), was discovered and structurally characterized.
- Detailed study of lattice parameter variations in the triclinic τ1 phase.
- Significant Al solubility was observed in the high-temperature modification of FeSi2, stabilizing it at lower temperatures.
- Experimental liquidus values showed significant deviations from CALPHAD predictions.
Conclusions:
- The study provides crucial experimental data for the Al-Fe-Si phase diagram.
- The discovery of the τ12 phase expands the known phase space of the system.
- Experimental results highlight the need for refinement of thermodynamic models for the Al-Fe-Si system.
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