Interactions between Nb-silicide based alloy and yttria mould during directional solidification
Source abstract
Abstract
Abstract Pure yttria moulds have been prepared for directional solidifications of Nb–22Ti–16Si–6Hf–2Al–2Cr (at. %) alloy with a withdrawal rate of 1 × 10 –4 m s –1 at 1850 °C and 1900 °C. This study demonstrates that a mild interface reaction occurred between the yttria mould and hafnium, the most reactive element in the alloy. A sequential reaction layer of HfO 2 and Y 2 O 3 was formed at metal–mould interface, and its thickness depended on both heating temperature and holding time. HfO 2 –Y 2 O 3 inclusions were dispersed in the metal matrix, and the majority of them concentrated around the solid–liquid interface rather than in steady state growth region. Some inclusions were merged with each other. The reaction mechanism between Nb-silicide based alloy and yttria mould also has been described.
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References (17)
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1. A study of the effects of Hf and Sn additions on the microstructure of Nbss/Nb5Si3 based in situ composites10.1016/j.intermet.2006.03.001 ↗
2. Effect of Mo addition on the phase stability of β-Nb5Si3 phase10.1016/j.intermet.2005.07.001 ↗
3. A review of very-high-temperature Nb-silicide-based composites10.1007/s11661-003-0269-8 ↗
4. Fracture toughness and high temperature strength of unidirectionally solidified Nb–Si binary and Nb–Ti–Si ternary alloys10.1016/j.jallcom.2006.01.071 ↗
5. Effect of growth rate on microstructure and mechanical properties in a directionally solidified Nb-silicide base alloy10.1016/j.matdes.2008.08.016 ↗
6. Processing high-temperature refractory-metal silicide in-situ composites10.1007/s11837-999-0077-8 ↗
7. Predicting thermodynamic stability of crucible oxides in molten titanium and titanium alloys10.1016/j.commatsci.2006.03.006 ↗
8. Thermodynamic properties of Y2O3 phases and the yttrium–oxygen phase diagram10.1016/S0925-8388(98)00245-X ↗
9. Interactions between TiAl alloys and yttria refractory material in casting process10.1016/j.jmatprotec.2010.03.003 ↗
10. On the evaluation of stability of rare earth oxides as face coats for investment casting of titanium10.1007/BF02667869 ↗
11. The manufacture of a niobium/niobium-silicide-based alloy using direct laser fabrication10.1016/j.jmatprotec.2008.04.042 ↗
12. Thermodynamic modeling of the yttrium–oxygen system10.1016/j.calphad.2007.01.010 ↗
13. Congruent vaporization properties as a tool for critical assessment of thermodynamic data The case of gaseous molecules in the La–O and Y–O systems10.1016/j.calphad.2004.03.001 ↗
14. Barin · 1997
15. Formation of Cr-modified silicide coatings on a Ti–Nb–Si based ultrahigh-temperature alloy by pack cementation process10.1016/j.apsusc.2010.05.091 ↗
16. Phase relations in the HfO2–Y2O3–Al2O3 system10.1016/j.calphad.2005.07.003 ↗
17. Directional dendritic solidification of a composite slurry: part II. Particle distribution10.1007/s11661-998-0259-y ↗