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.

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.

scholarly journals Microstructure Evolution and Mechanical Properties of Novel γ/γ′ Two-Phase Strengthened Ir-Based Superalloys

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1171
Author(s):  
Xiao Fang ◽  
Rui Hu ◽  
Jieren Yang ◽  
Yi Liu ◽  
Ming Wen
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Microstructure Evolution ◽  
Quaternary Alloys ◽  
Two Phase ◽  
Solid Solution Strengthening ◽  
New Class ◽  
High Temperature Mechanical Properties ◽  
Evolution Phase ◽  
Ultrahigh Temperature

Ir-based superalloys are irreplaceable in some specific harsh conditions regardless of their cost and high density. In order to develop a new class of Ir-based superalloy for future ultrahigh-temperature applications, the microstructure evolution, phase relationships, and mechanical properties of Ir–Al–W–Ta alloys with γ/γ′ two-phase structure were investigated. Room- and high-temperature compressions at 1300 °C, and room-temperature nanoindentation for the Ta-containing Ir–6Al–13W alloys were conducted. The results show that the addition of Ta can significantly improve the high-temperature mechanical properties, but does not change the fracture mode of the Ir-based two-phase superalloys. The compressive strength of quaternary alloys can be attributed to the precipitation of γ′-Ir3(Al, W) phase and solid solution strengthening. The microstructure and mechanical properties of Ir–Al–W–Ta quaternary alloys exhibit promising characteristics for the development of high-temperature materials.

scholarly journals Measurement Uncertainty Estimation for Laser Doppler Anemometer

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3847
Author(s):  
Karolina Weremijewicz ◽  
Andrzej Gajewski
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Regression Line ◽  
Estimation Algorithm ◽  
Calibration Procedure ◽  
Uncertainty Estimation ◽  
Two Phase ◽  
Mass And Heat Transfer ◽  
Preliminary Study ◽  
Measurement Uncertainty Estimation

Twenty percent of global electricity supplied to the buildings is used for preventing air temperature increase; its consumption for this prevention will triple by 2050 up to China’s present needs. Heat removed from the thermal power plants may drive cold generation in the absorption devices where mass and heat transfer are two-phase phenomena; hence liquid film break-up into the rivulets is extensively investigated, which needs knowledge of the velocity profiles. Laminar flow in a pipe is used in the preliminary study, velocity profile of developed flow is used as a benchmark. The study account writes the applied apparatus with their calibration procedure, and the uncertainty estimation algorithm. The calibration regression line with the slope close to one and a high Pearson’s coefficient value is the final outcome. Therefore, the apparatus may be applied in the principal research.

Determining the thermal power outputs of small high-temperature nuclear power plants

1976 ◽  
Vol 41 (6) ◽  
pp. 1076-1078
Author(s):  
A. I. El'tsov ◽  
A. K. Zabavin ◽  
Yu. A. Kotel'nikov ◽  
A. A. Labut ◽  
E. P. Larin ◽  
...  
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Thermal Power ◽  
Power Outputs

Development of a Thermal Energy Storage System for Parabolic Trough Power Plants With Direct Steam Generation

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Doerte Laing ◽  
Thomas Bauer ◽  
Dorothea Lehmann ◽  
Carsten Bahl
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Storage System ◽  
Thermal Power ◽  
Sensible Heat ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Two Phase ◽  
Solar Thermal Power ◽  
Direct Steam

For future parabolic trough plants direct steam generation in the absorber pipes is a promising option for reducing the costs of solar thermal power generation. These new solar thermal power plants require innovative storage concepts, where the two-phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e., for preheating of water and superheating of steam. A pinch analysis helps to recognize interface constraints imposed by the solar field and the power block and describes a way to dimension the latent and sensible components. Laboratory test results of a PCM test module with ∼140 kgNaNO3, applying the sandwich concept for enhancement of heat transfer, are presented, proving the expected capacity and power density. The concrete storage material for sensible heat was improved to allow the operation up to 500°C for direct steam generation. A storage system with a total storage capacity of ∼1 MWh is described, combining a PCM module and a concrete module, which will be tested in 2009 under real steam conditions around 100 bars.

Elevated Temperature Behavior of Creep and Fatigue in Welded P92 Steel

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1621-1626 ◽  
Author(s):  
Byeongsoo Lim ◽  
Bumjoon Kim ◽  
Moonhee Park ◽  
Sungjoon Won
Keyword(s):  
High Temperature ◽  
Weld Metal ◽  
Base Metal ◽  
Power Plants ◽  
Test Method ◽  
P92 Steel ◽  
Creep Properties ◽  
High Temperature Materials ◽  
Materials Used ◽  
Small Punch Creep Test

Fatigue strength and life of weldment at high temperature is very important for high temperature materials used in power plants. In this study, creep properties of weld metal, HAZ and base metal of P92 steel were evaluated by SP (small punch) creep test method. Fatigue crack growth behaviors in weld metal, HAZ and base metal of P92 steel were investigated at high temperature. Microstructure and microhardness of the weldment were also investigated for better analysis.

Sign in / Sign up

Export Citation Format

Share Document