| Abstrakt: |
The phase equilibria in the titanium-zirconium rich region of the ternary Ti-Zr-Si system have been studied in the temperature range from 1473 to 1323 K, together with microstructures pres-ent in the as-cast state. DTA, microscopy, X-ray diffraction (XRD), and chemical analysis by X-ray energy-dispersive spectroscopy have been employed. Whereas TiSi nucleates hetero-geneously and grows rapidly in titanium matrices, TiSi exhibits very slow precipitation kinetics. It also is displaced by (Ti, Zr)Si and a ternary silicide in ternary and more complex systems, explaining its absence in commercial alloys. Zirconium exhibits substantial solid solubility in TiSiin ternary alloys, while Ti exhibits only limited solubility in ZrSi, ZrSi, and ZrSi. Additionally, a new silicide of general formula (Ti, Zr)Si is formed in ternary alloys with a Ti:Zr ratio ranging from 2.26 to 0.68. Isothermal sections for the Ti-Zr-Si system are presented for temperatures of 1473 and 1323 K. [ABSTRACT FROM AUTHOR] |
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