Eutectic evolution of directionally solidified Nb-Si based ultrahigh temperature alloys
Source abstract
Abstract
Abstract The purpose of this work is to reveal the eutectic evolution in near-eutectic Nb-Si based alloys. The Nb–xTi–ySi–4Cr–2Al–2Hf (22Ti-15Si; 24Ti-15Si; 22Ti-16.5Si, at.%) alloys were processed by directional solidification with the withdrawal rates of 400 and 500 μm/s. Three typical eutectics were observed: quasi-regular eutectics I, quasi-regular eutectics II and eutectic dendrites colonies. The decrease in the content of Ti and the increase in the withdrawal rate increased the growth rate, and led to the transformation from quasi-regular eutectics I to quasi-regular eutectics II. The increase in the content of Si and the decrease in the withdrawal rate reduced the growth rate, led to larger degree of segregation, and eventually promoted the generation of eutectic dendrites colonies. The sizes of quasi-regular eutectics I and II decreased with the increase in the withdrawal rate and increased with the higher contents of Ti and Si. For the quasi-regular eutectics I and II, the volume fractions of γ-(Nb, Ti)5Si3 phases increased with increasing the content of Ti. Compared with the quasi-regular eutectics I, more γ-(Nb, Ti)5Si3 phases existed in the quasi-regular eutectics II, due to the growth pattern transition of the γ-(Nb, Ti)5Si3 phases.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (46)
Show source-provided references
1. The hotter the engine, the better10.1126/science.1179327 ↗
2. Alloy design for aircraft engines10.1038/nmat4709 ↗
3. A review of very-high-temperature Nb-silicide-based composites10.1007/s11661-003-0269-8 ↗
4. Phase diagrams for binary alloys
5. Microstructure evolution and room temperature deformation of a unidirectionally solidified Nb-22Ti-16Si-3Ta-2Hf-7Cr-3Al-0.2Ho (at.%) alloy10.1016/j.intermet.2010.08.015 ↗
6. Vacancy induced brittle-to-ductile transition of Nb5Si3 alloy from first-principles10.1016/j.matdes.2015.07.099 ↗
7. Microstructure, mechanical properties and fracture behavior of Nb with minor Si addition10.1016/j.ijrmhm.2016.04.004 ↗
8. Effect of B and Ti on the directionally solidified microstructure of the Nb–Si alloys10.1016/j.ijrmhm.2015.04.015 ↗
9. Microstructural and mechanical characterization of Nb-based in situ composites from Nb–Si–Ti ternary system10.1016/j.actamat.2007.08.012 ↗
10. Effect of growth rate on microstructure and mechanical properties in a directionally solidified Nb-silicide base alloy10.1016/j.matdes.2008.08.016 ↗
11. Microstructure and room-temperature fracture toughness of directionally solidified Nb–Si–Ti–Cr–Al–Hf alloy10.1016/j.msea.2012.10.011 ↗
12. Failure mode transition of Nb phase from cleavage to dimple/tear in Nb-16 Si-based alloys prepared via spark plasma sintering10.1016/j.matdes.2016.08.087 ↗
13. Microstructure and room temperature fracture toughness of Nbss/Nb5Si3 in situ composites10.1016/S0966-9795(01)00072-3 ↗
14. Microstructure and high temperature strength at 1773K of Nbss/Nb5Si3 composites alloyed with molybdenum10.1016/S0966-9795(02)00041-9 ↗
15. Solidification process and mechanical behavior of the Nb/Nb5Si3 two phase alloys in the Nb-Ti-Si system10.2320/matertrans.45.3264 ↗
16. Fracture toughness and high temperature strength of unidirectionally solidified Nb–Si binary and Nb–Ti–Si ternary alloys10.1016/j.jallcom.2006.01.071 ↗
17. Mechanical properties of directionally solidified Nb–Mo–Si-based alloys with aligned Nbss/Nb5Si3 lamellar structure10.1016/j.msea.2011.04.011 ↗
18. Microstructures and mechanical properties of directionally solidified multi-element Nb-Si alloy10.1016/S1002-0071(12)60048-3 ↗
19. Eutectic formation during directional solidification: effect of the withdrawal rate10.1016/j.matlet.2012.11.002 ↗
20. Microstructure evolution of directionally solidified Nb–Si alloy10.1179/1743284713Y.0000000430 ↗
21. Microstructure transition from lamellar eutectic to anomalous eutectic of Nb-Si based alloy powders by heat treatment and spark plasma sintering10.1016/j.jallcom.2016.11.236 ↗
22. Microstructure evolution of Ti-47Al-2Cr-2Nb alloy in the liquid-metal-cooling (LMC) directional-solidification process10.1007/s11595-011-0196-2 ↗
23. Heat flow in controlled directional solidification of metals: I. Experimental investigation10.1016/0022-0248(80)90014-7 ↗
24. Heat flow in controlled directional solidification of metals: II. Mathematical model10.1016/0022-0248(80)90015-9 ↗
25. Alloying and phase stability in niobium silicide in-situ composites
26. Towards the improvement of the oxidation resistance of Nb-silicides in situ composites: a solid state diffusion approach10.1016/j.corsci.2013.10.033 ↗
27. Study of the role of Ta and Cr additions in the microstructure of Nb–Ti–Si–Al in situ composites10.1016/j.intermet.2005.10.005 ↗
28. Study of the microstructures and oxidation of Nb–Si–Cr–Al–Mo in situ composites alloyed with Ti, Hf and Sn10.1016/j.intermet.2006.08.016 ↗
29. Study of the role of Al, Cr and Ti additions in the microstructure of Nb–18Si–5Hf base alloys10.1016/j.intermet.2009.07.020 ↗
30. Effect of interlayers in ceramic-metal joints with thermal expansion mismatches10.1111/j.1151-2916.1984.tb19688.x ↗
31. Expansion and elastic moduli of the silicide based intermetallic alloys Ti5Si3 (X) and Nb5Si310.1016/S1359-6462(97)00496-X ↗
32. Effects of B addition on the microstructure and properties of Nb silicide based ultrahigh temperature alloys10.1016/j.intermet.2014.10.007 ↗
33. Barin · 1997
34. Ultrahigh-temperature Nbss/Nb5Si3 fully-lamellar microstructure developed by directional solidification in OFZ furnace10.1016/j.intermet.2010.10.024 ↗
35. Thermochemical data for Transition-Metal-Si systems
36. Growth kinetics of solid-liquid Ga interfaces: part I. Experimental10.1007/BF02660658 ↗
37. Development of Al–Si–Zn–Sr filler metals for brazing 6061 aluminum alloy10.1016/j.matdes.2012.06.031 ↗
38. Graphite crystals grown within electromagnetically levitated metallic droplets10.1016/j.actamat.2012.09.019 ↗
39. Influence of withdrawal rate on the microstructure of Ni-base single-crystal superalloys containing Re and Ru10.1016/j.jallcom.2011.02.156 ↗
40. Influence of directional solidification variables on the microstructure and crystal orientation of AM3 under high thermal gradient10.1007/s10853-010-4696-9 ↗
41. Influence of withdrawal rate on last stage solidification path of a Mo-rich Ni3Al based single crystal superalloy10.1016/j.jallcom.2014.11.048 ↗
42. Growth of lamellar eutectic dendrites in undercooled melts10.1063/1.368233 ↗
43. Eutectic growth in bulk undercooled melts10.1016/j.actamat.2005.01.042 ↗
44. Solidification microstructures of the undercooled Co–24at% Sn eutectic alloy containing 0.5 at% Mn10.1016/j.matdes.2015.06.010 ↗
45. Remelting-induced anomalous eutectic formation during solidification of deeply undercooled eutectic alloy melts10.1016/j.actamat.2015.05.014 ↗
46. Alloying effects on the fracture toughness of Nb-based silicides and Laves phases10.1016/j.msea.2005.06.077 ↗