Phase Equilibria in the Nb-rich Nb-Ti-Si-Cr-Hf alloys

2011 ◽  
Vol 1295 ◽  
Author(s):  
Ying Yang ◽  
Bernard P. Bewlay ◽  
Austin Chang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Phase Equilibria ◽  
Calphad Approach ◽  
Rich Region ◽  
Isothermal Sections ◽  
Beneficial Effects ◽  
High Temperature Materials ◽  
Ti Alloys ◽  
Alloying Effects

ABSTRACTRefractory Metal-Intermetallic Composites (RMICs) based on the Nb-Si system have been considered as candidates for the next-generation high temperature materials (i.e. >1200°C). Ti, Cr and Hf have been shown to have beneficial effects on the oxidation resistance and mechanical properties of Nb-Si alloys. The present study has determined phase equilibria in the Nb-rich region of the Nb-Si-Ti-Cr-Hf system via the Calphad approach. The alloying effects of Cr and Hf on the microstructure of Nb-Si-Ti alloys are understood based on isothermal sections, liquidus projections, and solidification curves that were calculated from the thermodynamic models of the Nb-Ti-Si-Cr-Hf system developed in the present study. This work provides important guidelines on the development of new Nb-Si-Ti-Cr-Hf alloys.

Effect of Cr Addition on the Multiphase Equilibria in the Nb-rich Nb-Si-Ti System - Thermodynamic Modeling and Designed Experiments

2008 ◽  
Vol 1128 ◽  
Author(s):  
Ying Yang ◽  
Bernard P Bewlay ◽  
Shuanglin chen ◽  
M R Jackson ◽  
Y. A. Chang
Keyword(s):  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Thermodynamic Description ◽  
Designed Experiments ◽  
Beneficial Effects ◽  
High Temperature Materials ◽  
Ti Alloys ◽  
Multiphase Equilibria ◽  
Cr Addition ◽  
Alloying Effects

AbstractRefractory Metal Intermetallic Composites (RMICs) based on the Nb-Si system are considered as candidates of next-generation high temperature materials (i.e. >1200°C). Ti and Cr have been shown to have beneficial effects on the oxidation resistance and mechanical properties of Nb-Si alloys. Phase equilibria in the Nb-Si-Ti system have been studied in detail. The present study has investigated multiphase equilibria in the Nb-Si-Ti alloys with Cr additions via an approach of integrating thermodynamic modeling with designed experiments. The alloying effects of Cr on the microstructure of the Nb-Si-Ti alloys are described using both phase equilibria and solidification paths that were calculated from the thermodynamic description of the Nb-Cr-Si-Ti system developed in the present study.

Phase equilibrium and mechanical properties of Cr-Mo-Nb-Si-B alloys Composed of BCC and T2-silicide phase

MRS Advances ◽  
2019 ◽  
Vol 4 (25-26) ◽  
pp. 1491-1496 ◽  
Author(s):  
Daisuke Goto ◽  
Ken-ichi Ikeda ◽  
Seiji Miura
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Phase Equilibria ◽  
Power Plants ◽  
Thermal Power ◽  
Silicide Phase ◽  
Two Phase ◽  
New Class ◽  
High Temperature Materials ◽  
Si Content

ABSTRACTA new class of high-temperature materials based on refractory elements was investigated with an aim to improve the energy efficiency of thermal power plants. Alloys based on Nb and Mo composed of BCC solid solution (BCCss) (Nb-Mo) and T2-silicide (Nb,Mo)5(Si,B)3 are promising candidates as high-temperature materials. Further investigation on the alloy phase equilibria of this system is required to improve the mechanical properties and oxidation resistance through optimization of the phase compositions. Cr is one candidate to modify the properties of the alloy because Cr is expected to stabilize the T2 compound phase along with B. Here, the phase equilibria among BCCss and the T2 compound are widely investigated in the Cr-Mo-Nb-Si-B system, and a BCCss-T2 two-phase microstructure is found in Mo-rich alloys. The B/Si ratio in the T2 phase increases with the Cr content, while almost no B solubility was found in BCCss. As the Si content increases in alloys, the A15 silicide phase ((Cr, Mo, Nb)3Si) and/or Laves phase appear.Nanoindentation tests were conducted to investigate the mechanical properties of the BCCss phase of the alloys in the Cr-Mo-Nb-Si-B system. The nanohardness and reduced elastic modulus of these alloys tended to be higher with an increase in Cr.

scholarly journals The high-temperature phase equilibria of the Ni–Sn–Zn system: Isothermal sections

2011 ◽  
Vol 19 (10) ◽  
pp. 1489-1501 ◽  
Author(s):  
Clemens Schmetterer ◽  
Divakar Rajamohan ◽  
Herbert Ipser ◽  
Hans Flandorfer
Keyword(s):  
High Temperature ◽  
Phase Equilibria ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Isothermal Sections

Effect of Zr Addition on High Temperature Mechanical Properties of Near Alpha Ti-Al-Zr-Sn Based Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 580-583 ◽  
Author(s):  
Murugesan Jayaprakash ◽  
De Hai Ping ◽  
Y. Yamabe-Mitarai
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Test Results ◽  
High Temperature Mechanical Properties ◽  
Ti Alloys ◽  
Zr Addition ◽  
And Performance ◽  
Compressive Tests

Titanium (Ti) alloys are widely used in aerospace industries successfully up to 600°C. Increasing the operating temperature and performance of these alloys would be very useful for fuel economy. Numerous numbers of research works has been focused on the improvement of the high temperature performances of Ti alloys. It has been well known that Zirconium (Zr) is one of the important solid-solution strengthener in Ti-alloys. In the present study, the effect of Zr addition on the microstructure and mechanical properties of the near–α Ti-Al-Zr-Sn based alloys has been investigated.The compression test results showed that Zr addition significantly improves both room temperature and high temperature strength. The results obtained were explained based on the microstructural observation, room temperature and high temperature compressive tests.

Mechanical properties of near alpha titanium alloys for high-temperature applications - a review

2020 ◽  
Vol 92 (4) ◽  
pp. 521-540 ◽  
Author(s):  
Vitus Mwinteribo Tabie ◽  
Chong Li ◽  
Wang Saifu ◽  
Jianwei Li ◽  
Xiaojing Xu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Temperature ◽  
Titanium Alloys ◽  
Content Type ◽  
The Past ◽  
Ti Alloys ◽  
Multiaxial Compression ◽  
Aero Engines ◽  
Temperature Applications

Purpose This paper aims to present a broad review of near-a titanium alloys for high-temperature applications. Design/methodology/approach Following a brief introduction of titanium (Ti) alloys, this paper considers the near-α group of Ti alloys, which are the most popular high-temperature Ti alloys developed for a high-temperature application, particularly in compressor disc and blades in aero-engines. The paper is relied on literature within the past decade to discuss phase stability and microstructural effect of alloying elements, plastic deformation and reinforcements used in the development of these alloys. Findings The near-a Ti alloys show high potential for high-temperature applications, and many researchers have explored the incorporation of TiC, TiB SiC, Y2O3, La2O3 and Al2O3 reinforcements for improved mechanical properties. Rolling, extrusion, forging and some severe plastic deformation (SPD) techniques, as well as heat treatment methods, have also been explored extensively. There is, however, a paucity of information on SiC, Y2O3 and carbon nanotube reinforcements and their combinations for improved mechanical properties. Information on some SPD techniques such as cyclic extrusion compression, multiaxial compression/forging and repeated corrugation and straightening for this class of alloys is also limited. Originality/value This paper provides a topical, technical insight into developments in near-a Ti alloys using literature from within the past decade. It also outlines the future developments of this class of Ti alloys.

Phase Equilibria in the Ni–Rich Region of the Ni–Al–Zr System

1982 ◽  
Vol 19 ◽  
Author(s):  
C.S. Jayanth ◽  
P. Nash
Keyword(s):  
High Temperature ◽  
Phase Equilibria ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
High Strength ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Detailed Knowledge ◽  
Isothermal Sections

ABSTRACTAlloys from the Ni–rich corner of the Ni–Al–Zr system have potential for use in high temperature, high strength applications. Such applications require a detailed knowledge of the high temperature phase equilibria.In the case of the Ni–Al–Zr system no isothermal sections have been published although the existence of a monovariant eutectic valley between Ni3Al and Ni7Zr2 has been established. An experimental determination of the phase equilibria in this system is being carried out using quantitative electron microprobe analysis (JEOL JSM–U3), xray diffraction and optical metallography. Partial isothermal sections are being determined for 1373K (1100°C) and 1273K (1000°C) and the resulting phase equilibria compared to that in the Ni–Al–Hf system determined previously.

Effect of Cr Addition on the Phase Equilibria of the Nb-Si System

2006 ◽  
Vol 980 ◽  
Author(s):  
B. P. Bewlay ◽  
Y. Yang ◽  
R. L. Casey ◽  
M. R. Jackson ◽  
Y. A. Chang
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Phase Equilibria ◽  
Thermodynamic Description ◽  
Directionally Solidified ◽  
Isothermal Sections ◽  
Environmental Properties ◽  
Structural Applications ◽  
Cr Addition

AbstractNb-silicide based in-situ composites are promising materials for future high-temperature structural applications. Nb-silicide composites are typically alloyed with Hf, Ti, Cr, and Al to provide a balance of mechanical and environmental properties. A thermodynamic description of the Nb-Cr-Si system has been developed previously in literature based on reported isothermal sections. According to the previously calculated phase diagrams, selected alloys were directionally solidified. The as-solidified microstructures could not be interpreted using the liquidus projection calculated from the existing thermodynamic descriptions. Therefore, an improved thermodynamic description was developed by incorporating the new experimental data.

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