Deformation Mechanisms in Niobium Silicide-Based Composites

Bewlay, B. P.; Jackson, M. R.; Briant, C. L.

doi:10.21236/ada387385

Cited by 5 publications

(2 citation statements)

References 32 publications

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“…The Si concentration was set at 18 at.% as Nb-silicide based alloys were reported to have minimum secondary creep rate at this composition [5]. The Ti concentration was selected on the basis of previous work [6][7][8] as it was aimed to maintain the melting temperature of the alloy above 1700 o C. The alloys were prepared by arc melting high purity elements in a copper water-cooled crucible under high purity argon atmosphere with a non-consumable electrode.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Ge and Ti Additions on the Microstructures and Properties of Nb-18Si Based Alloys

Tsakiropoulos

2011

MRS Proc.

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The effects of Ge and Ti additions on the microstructure, hardness and oxidation behaviour of the alloys Nb-18Si-5Ge (ZF1) and Nb-24Ti-18Si-5Ge (ZF3) were studied. The as cast microstructure of the alloy ZF1 consisted of Nb ss (cI2), and Nb 5 Si 3 (tI32) with the latter being the primary phase and the two phases forming high volume fractions of Nb ss + Nb 5 Si 3 eutectic. The Ge addition stabilised the Nb 5 Si 3 (tI32), and destabilised the Nb 3 Si (tP32) and the Nb ss + Nb 3 Si eutectic. After heat treatment at 1200 °C for 100 h the Nb 5 Si 3 (tI32) was partially transformed to the Nb 5 Si 3 (tI32), and equilibrium was reached after heat treatment at 1500 °C for 100 h. The phases present in the as cast alloy ZF3 were the Nb ss (cI2), and the Nb 3 Si (tP32), Nb 5 Si 3 (tI32) and Ti 5 Si 3 (hP16) silicides, with the latter forming a eutectic with the solid solution. The same phases were present after heat treatment at 1200 °C for 100 h but only the Nb ss , and the Nb 3 Si and Nb 5 Si 3 silicides were present after 100 h at 1500 °C where TiO 2 was also formed. The Ge addition increased the microhardness of the Nb 5 Si 3 . The synergy of Ti with Ge resulted in a strong hardening effect and a remarkable retention of the hardness of the alloy ZF3. The additions of Ge and Ti to the Nb-18Si alloy improved the oxidation resistance at 800 °C, but pest oxidation behaviour was not eliminated.

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Section: Methodsmentioning

confidence: 99%

The Effect of Ge and Ti Additions on the Microstructures and Properties of Nb-18Si Based Alloys

Tsakiropoulos

2011

MRS Proc.

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“…for use in such applications [5][6][7][8][9] , because they show good creep resistance and room temperature fracture toughness, however, the low oxidation resistance has yet to be addressed [6,10] . In these materials, Cr, Hf, Ti, B and Al may be added to improve their properties [1,5,9,[11][12][13][14][15][16][17] . The Cr2X Laves compounds (X -Hf, Nb, Ta, Ti, Zr) present, in general, interesting properties such as low density, high corrosion and oxidation resistance as well as microstructural stability for applications at high temperatures [18] .…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Cr-Hf-Nb System: Liquidus Projection and 1200 °C Isothermal Section

Gigolotti

Silva

Coelho

et al. 2020

J. Phase Equilib. Diffus.

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Phase equilibria data from ternary Cr-Nb-X (X = Hf, Ta, Ti, Zr) systems are relevant to the development of Niobium-silicide based composites for use in jet engines. Such systems present at several temperatures a pseudo-binary of Cr2Nb-Cr2X Laves phases. This work presents the experimentally determined liquidus projection and the 1200 °C isothermal section for the Cr-Hf-Nb system based on microstructural characterization of as-cast and heat-treated alloys. The microstructural characterization using X-ray diffractometry, scanning electron microscopy and electron probe microanalysis showed four eutectic-type monovariant reactions and two class II invariant reactions in the liquidus projection. The

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Phase Equilibrium and High-Temperature Mechanical Properties of Nb–Si–X Ternary Alloys

Matsunaga,

Komamura,

Yamabe-Mitarai

2023

Metall Mater Trans A

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Phase equilibrium of Nb–Si–X ternary alloys (X = Zr, Ta, Al) was predicted by thermodynamic calculations. Microstructure characterization and phase identification have been performed to investigate the phase equilibrium and validate the prediction. High-temperature compression tests were performed to evaluate the mechanical properties. All alloys exhibited ssNb, Nb5Si3, and Nb3Si phases. Zr addition increased strength at both room and elevated temperatures. The alloy with large primary silicide islands exhibited a higher 0.2 pct proof stress.

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Deformation Mechanisms in Niobium Silicide-Based Composites

Cited by 5 publications

References 32 publications

The Effect of Ge and Ti Additions on the Microstructures and Properties of Nb-18Si Based Alloys

The Effect of Ge and Ti Additions on the Microstructures and Properties of Nb-18Si Based Alloys

Experimental Study of the Cr-Hf-Nb System: Liquidus Projection and 1200 °C Isothermal Section

Phase Equilibrium and High-Temperature Mechanical Properties of Nb–Si–X Ternary Alloys

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