Phase equilibria and structural investigations in the system Al-Fe-Si.
Phase equilibria and structural investigations in the system Al-Fe-Si.
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DOI：
10.1016/j.intermet.2011.05.003
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发表时间：
2011-12
期刊：
影响因子：
4.4
通讯作者：
Richter KW
中科院分区：
文献类型：
--
作者：
Marker MC;Skolyszewska-Kühberger B;Effenberger HS;Schmetterer C;Richter KW
研究了Al-Fe-Si体系在800℃富al部分和900℃富fe部分的等温截面，以及在27、35、40、50和60℃的6个垂直截面。% Fe和5 at。采用光学显微镜和粉末x射线衍射（XRD）对样品进行初步表征，并用电子探针微分析（EPMA）和扫描电镜（SEM）对退火样品进行精确的相组成测定。用差热分析（DTA）研究了热反应。我们的实验结果与Al-Fe-Si体系的最新相图版本基本一致。发现了一种新的三元高温相τ12 （cF96， niti2型），成分为Al48Fe36Si16，并通过单晶和粉末XRD对其结构进行了表征。详细研究了三斜相τ1的晶格参数随Al2+xFe3Si3−x（−0.3 < x < 1.3）的变化规律。对于二相FeSi2， Al在低温改性LT-FeSi2 （ζβ）中溶解度小，而在高温改性HT-FeSi2 （ζα）中溶解度大（8.5 at）。% Al)。发现FeSi2的高温改性在三元体系中稳定到更低的温度，证实了早期文献对此问题的建议。四个选定的垂直剖面的DTA结果与基于最近CALPHAD评估的计算剖面进行了比较。液相值的偏差较大，表明热力学模型有待改进。
The Al–Fe–Si system was studied for an isothermal section at 800 °C in the Al-rich part and at 900 °C in the Fe-rich part, and for half a dozen vertical sections at 27, 35, 40, 50 and 60 at.% Fe and 5 at.% Al. Optical microscopy and powder X-ray diffraction (XRD) was used for initial sample characterization, and Electron Probe Microanalysis (EPMA) and Scanning Electron Microscopy (SEM) of the annealed samples was used to determine the exact phase compositions. Thermal reactions were studied by Differential Thermal Analysis (DTA). Our experimental results are generally in good agreement with the most recent phase diagram versions of the system Al–Fe–Si. A new ternary high-temperature phase τ12 (cF96, NiTi2-type) with the composition Al48Fe36Si16 was discovered and was structurally characterized by means of single-crystal and powder XRD. The variation of the lattice parameters of the triclinic phase τ1 with the composition Al2+xFe3Si3−x (−0.3 < x < 1.3) was studied in detail. For the binary phase FeSi2 only small solubility of Al was found in the low-temperature modification LT-FeSi2 (ζβ) but significant solubility in the high-temperature modification HT-FeSi2 (ζα) (8.5 at.% Al). It was found that the high-temperature modification of FeSi2 is stabilized down to much lower temperature in the ternary, confirming earlier literature suggestions on this issue. DTA results in four selected vertical sections were compared with calculated sections based on a recent CALPHAD assessment. The deviations of liquidus values are significant suggesting the need for improvement of the thermodynamic models.