High-Temperature Irradiation of Alumina-Base Ceramic Materials in a Water Cooled Fission Reactor

2009 ◽  
pp. 1255-1255-11
Author(s):  
T Shikama ◽  
M Narui ◽  
H Kayano ◽  
T Sagawa ◽  
T Tanabe ◽  
...  
Keyword(s):  
High Temperature ◽  
Ceramic Materials ◽  
Fission Reactor ◽  
Base Ceramic ◽  
Temperature Irradiation

scholarly journals Superalloy Technology - A Perspective on Critical Innovations for Turbine Engines

2008 ◽  
Vol 380 ◽  
pp. 113-134 ◽  
Author(s):  
Robert Schafrik ◽  
Robert Sprague
Keyword(s):  
High Temperature ◽  
Customer Value ◽  
Oil And Gas ◽  
Driving Forces ◽  
Ceramic Materials ◽  
Nickel Superalloy ◽  
Engineering Practice ◽  
Jet Engines ◽  
Societal Benefit ◽  
Development Paradigm

High temperature structural materials, such as nickel-based superalloys, have contributed immensely to societal benefit. These materials provide the backbone for many applications within key industries that include chemical and metallurgical processing, oil and gas extraction and refining, energy generation, and aerospace propulsion. Within this broad application space, the best known challenges tackled by these materials have arisen from the demand for large, efficient land-based power turbines and light-weight, highly durable aeronautical jet engines. So impressive has the success of these materials been that some have described the last half of the 20th century as the Superalloy Age. Many challenges, technical and otherwise, were overcome to achieve successful applications. This paper highlights some of the key developments in nickel superalloy technology, principally from the perspective of aeronautical applications. In the past, it was not unusual for development programs to stretch out 10 to 20 years as the materials technology was developed, followed by the development of engineering practice, and lengthy production scaleup. And many developments fell by the wayside. Today, there continue to be many demands for improved high temperature materials. New classes of materials, such as intermetallics and ceramic materials, are challenging superalloys for key applications, given the conventional wisdom that superalloys are reaching their natural entitlement level. Therefore, multiple driving forces are converging that motivate improvements in the superalloy development process. This paper concludes with a description of a new development paradigm that emphasizes creativity, development speed, and customer value that can provide superalloys that meet new needs.

scholarly journals Study of Resistance to Helium Swelling of Lithium-Containing Ceramics under High-Temperature Irradiation

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1350
Author(s):  
Dmitriy I. Shlimas ◽  
Artem L. Kozlovskiy ◽  
Askar Kh. Syzdykov ◽  
Daryn B. Borgekov ◽  
Maxim V. Zdorovets
Keyword(s):  
Surface Layer ◽  
High Temperature ◽  
Radiation Damage ◽  
Thermal Annealing ◽  
Reactor Core ◽  
Strength Properties ◽  
Radiation Defects ◽  
Temperature Irradiation ◽  
Thermal Sintering ◽  
Damage Processes

The aim of this work was to study resistance to helium accumulation processes in the structure of the surface layer of lithium-containing ceramics and the subsequent destruction and embrittlement processes, depending on radiation fluence. The objects of study were Li2TiO3-type ceramics obtained by thermal sintering. The fluence dependency of changes in the structural and strength properties of ceramics was determined to be in the range from 1018 to 1022 ion/m2, which corresponded to the concentration of implanted helium from 0.01% to 0.8–1 at.%. Irradiation was carried out at a temperature of 700 °C, which made it possible to simulate the processes of radiation damage that were closest to the real conditions in the reactor core. During the studies carried out, it was found that, at irradiation fluences of 1018–1020 ion/m2, the formation of point radiation defects was equaled by the process of thermal annealing of defects, as a result of which the concentration of defects and their effect on the change in the structural and strength properties of ceramics were insignificant. An increase in the concentration of implanted helium in the structure of the surface layer to above 0.5 at.% led to the dominance of radiation damage processes over the annealing of defects and the formation of gas-filled cavities, which negatively affects the strength of ceramics.

Silicon carbide fibers and whiskers for ceramic matrix composites (review)

2021 ◽  
Vol 87 (8) ◽  
pp. 51-63
Author(s):  
A. M. Shestakov
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
High Temperature ◽  
Composite Materials ◽  
Ceramic Matrix Composites ◽  
Ceramic Materials ◽  
Ceramic Composites ◽  
Silicon Compounds ◽  
Reinforcing Fillers ◽  
Operating Temperatures

An increase the operating temperature range of structural elements and aircraft assemblies is one of the main goals in developing advanced and new models of aerospace equipment to improve their technical characteristics. The most heat-loaded aircraft structures, such as a combustion chamber, high-pressure turbine segments, nozzle flaps with a controlled thrust vector, must have a long service life under conditions of high temperatures, an oxidizing environment, fuel combustion products, and variable mechanical and thermal loads. At the same time, modern Ti and Ni-based superalloys have reached the limits of their operating temperatures. The leading world aircraft manufacturers — General Electric (USA), Rolls-Royce High Temperature Composite Inc. (USA), Snecma Propulsion Solide (France) — actively conduct fundamental research in developing ceramic materials with high (1300 – 1600°C) and ultrahigh (2000 – 2500°C) operating temperatures. However, ceramic materials have a number of shortcomings attributed to the high brittleness and low crack resistance of monolithic ceramics. Moreover, manufacturing of complex configuration and large-sized ceramic parts faces serious difficulties. Nowadays, ceramic composite materials with a high-temperature matrix (e.g., based on ZrC-SiC) and reinforcing filler, an inorganic fiber, (e.g., silicon carbide) appeared most promising for operating temperatures above 1200°C and exhibited enhanced energy efficiency. Ceramic fibers based on silicon compounds possess excellent mechanical properties: the tensile strength more than 2 GPa, modulus of elasticity more than 200 GPa, and thermal resistance at a temperature above 800°C, thus making them an essential reinforcing component in metal and ceramic composites. This review is devoted to silicon carbide core fibers obtained by chemical vapor deposition of silicon carbide onto a tungsten or carbon core, which makes it possible to obtain fibers a 100 – 150 μm in diameter to be used in composites with a metal matrix. The coreless SiC-fibers with a diameter of 10 – 20 μm obtained by molding a polymer precursor from a melt and used mainly in ceramic composites are also considered. A comparative analysis of the phase composition, physical and mechanical properties and thermal-oxidative resistance of fibers obtained by different methods is presented. Whiskers (filamentary crystals) are also considered as reinforcing fillers for composite materials along with their properties and methods of production. The prospects of using different fibers and whiskers as reinforcing fillers for composites are discussed.

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