The role of Fe and Ti additions in the microstructure of Nb–18Si–5Sn silicide-based alloys

Vellios, Nikos; Tsakiropoulos, P.

doi:10.1016/j.intermet.2007.06.001

Cited by 54 publications

(78 citation statements)

References 18 publications

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“…The Nb silicide based alloys have microstructures that consist of an Nb solid solution phase (Nb ss ) and silicide(s) (for example Nb 3 Si, Nb 5 Si 3 ) and other intermetallic phase(s) (for example A15 compounds such as Nb 3 Al, Nb 3 Sn, Nb 3 Ge, C14 NbCr 2 Laves). The volume fractions of the aforementioned phases depend on alloy composition and processing [1][2][3][4][5]. The choice of alloy composition is influenced by the processing route and considerations about achieving a balance of high and ambient temperature mechanical properties and oxidation resistance [1,2,6,7].…”

Section: Introductionmentioning

confidence: 99%

“…The spatial distribution of the Nb ss and its volume fraction and chemical composition are critical for the properties of Nb silicide based alloys [2][3][4][5][8][9][10]. In these materials creep and high temperature strength and oxidation resistance are provided by the silicide(s) and intermetallic phase(s) and ambient temperature ductility and fracture toughness by the Nb ss , which is expected to impart ductile phase toughening [1,2,11].…”

Section: Introductionmentioning

confidence: 99%

“…In these materials creep and high temperature strength and oxidation resistance are provided by the silicide(s) and intermetallic phase(s) and ambient temperature ductility and fracture toughness by the Nb ss , which is expected to impart ductile phase toughening [1,2,11]. The chemical composition of the silicides is affected by the alloying additions, for example in Nb 5 Si 3 the Nb can be substituted by Hf, Ti, Mo, W and the Si by Al, B, Ge, Sn [3][4][5][8][9][10][12][13][14] and thus their elevated and ambient temperature properties are also dependent on alloy chemistry [3,[10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, even though the maximum solid solubility of Si in Nb is low, the actual Si content in the latter depends on alloy composition and Nb ss with/out Si content can form in the microstructure [5,8,17]. Thus, in Nb silicide based alloys it is possible to have (Nb, TM, RM, simple metal, metalloid) solid solution, (Nb ss ), where TM is transition metal (e.g., Cr, Hf, Ti), RM is refractory metal (e.g., Mo, Ta, W), and the simple metal(s) and metalloid(s) respectively can be Al, Sn and B and Ge [3][4][5][6][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ab initio investigation of the Nb–Al system

Papadimitriou

Utton

Tsakiropoulos

2015

Computational Materials Science

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ab initio investigation of the Nb–Al system

Papadimitriou

Utton

Tsakiropoulos

2015

Computational Materials Science

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“…Furthermore, Sn can stabilise metastable forms of the Nb 3 Si when it is in synergy with Fe and Cr [13]. The formation of A15-Nb 3 Al in Nb silicide based alloys is possible depending on the Ti/Al ratio in the alloy [14].…”

Section: Introductionmentioning

confidence: 99%

Ab Initio Study of Binary and Ternary Nb3(X,Y) A15 Intermetallic Phases (X,Y = Al, Ge, Si, Sn)

Papadimitriou

Utton

Scott

et al. 2014

Metall Mater Trans A

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Elastic and thermodynamic properties of binary and ternary A15 phases containing Al, Ge, Si and Sn were studied using the first-principles pseudopotential plane-wave method based on density functional theory. The temperature dependence of the enthalpy of formation for the A15 intermetallics is reported using the quasiharmonic approximation. Elastic properties of the studied compounds were calculated at T = 0 K and were in agreement with the measured values reported in the literature. The elastic properties and thermodynamic data for the metastable A15-Nb 3 Si are reported for the first time. The Nb 3 Si has the highest bulk, shear and Young's modulus values and is predicted to be less ductile than the other three binary A15 intermetallics. The calculations suggest (i) that Al and Sn have a positive effect on the ductility of the A15 compounds of this study, (ii) that Ge as a ternary addition has a ductilizing effect only in the A15-Nb 3 Si, and (iii) that Si as a ternary addition has a negative effect on the ductility of all the A15 compounds of the present study. The linear thermal expansion coefficients of the Nb, Al, the A15 Nb 3 Al, Nb 3 Ge, Nb 3 Sn and Nb 3 Si (A15) phases are reported. The Sn and Al additions in the Nb 3 Si stabilise the A15 structure, while the Ge addition has the opposite effect, stabilising the tP32 Nb 3 Si. * Corresponding author: p.tsakiropoulos@sheffield.ac.uk, fax +440(0)1142225943

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Beyond Nickel Based Superalloys

Tsakiropoulos

2010

Encyclopedia of Aerospace Engineering

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In the most advanced gas turbine engines, the gas temperature exceeds the melting temperature of Ni based superalloys. Further improvements in the performance of gas turbines require operation of metallic materials at higher temperatures. Research programs on Nb and Mo silicide based alloys have demonstrated that these materials can offer attractive mechanical properties that justify their consideration as suitable candidate materials to replace Ni based superalloys in specific structural applications in gas turbine engines. The research has also demonstrated that oxidation behavior of developmental alloys can be significantly improved via selection of specific alloy elements. The ongoing research to develop new alloys is outlined with the emphasis on new metallic materials based on the refractory metals Nb and Mo. For the Nb based alloys, alloy development research based on the Nb–Si–Ti system with transition/refractory and free electron metal additions is reviewed. For the Mo based alloys, the review concentrates on alloys based on the Mo–Si–B and Mo–Si–Al systems.

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The role of Fe and Ti additions in the microstructure of Nb–18Si–5Sn silicide-based alloys

Cited by 54 publications

References 18 publications

Ab initio investigation of the Nb–Al system

Ab initio investigation of the Nb–Al system

Ab Initio Study of Binary and Ternary Nb3(X,Y) A15 Intermetallic Phases (X,Y = Al, Ge, Si, Sn)

Beyond Nickel Based Superalloys

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