As an analogy to nickel-based superalloys, ferritic superalloys based on Fe-Al-Cr-Ni-Ti are proposed for high-temperature applications, especially for fossil-energy power systems. Integrated computational tools will be employed to investigate thermodynamic, kinetic, and meso-scale properties of the proposed alloy systems. Meanwhile, selected microstructural attributes in representative model fe...

Superalloys are a class of materials that possess stable microstructures at elevated temperatures due to the presence of coherent L12 ordered γ’ precipitates spatially aligned along elastically soft directions in a face centered cubic (FCC) γ matrix [1]. Nickel-base superalloys are used in a variety of applications such as in turbine blades of aircraft engines and land-based turbine engine [1]....

The aerospace industry is one of the biggest consumers of advanced materials because of its unique combination of mechanical and physical properties and chemical stability. Highly alloyed stainless steel, titanium alloys and nickel based superalloys are mostly used for aerospace applications. High alloyed stainless steel is used for the shafts of aero engine turbines, titanium alloys for compre...

Ni based superalloys can be welded by diffusion bonding. Temperature, diffusion coefficient, activation energy and Boltzmann constant influence the quality of diffusion bonding, so obtaining the best condition for welding is considered. Showing the suitable condition for diffusion welding of nickel-based superalloys is the aim of this paper.

Increased operating temperatures and higher efficiency in gas turbines and jet engines can reduce CO2 emission, thus contributing to the prevention of global warming. To achieve this goal, it is essential to improve the properties of high temperature materials. Various Ni-base superalloys are used for high-temperature components, e.g., combustors and high-pressure turbine blades and vanes, that...

This paper is focused on microstructure of protective layers created by co-deposition of Al and Si on nickel base superalloys INCO 713 LC and INCO 738 LC after thermal and thermal-stress exposition and on microstructure of basic materials (substrates). The contribution also shows creep tests results for both superalloys with and without a protective layer.

When significant resistance to loading under static, fatigue and creep conditions is required, the superalloys have emerged as the materials of choice for high temperature applications. This is particularly true when operating temperatures are beyond about 800C. This is the case for gas turbines used for (i) jet propulsion, e.g. the 100,000 lb thrust engines used for powering large two-engined ...

The chemical, physical, and mechanical characteristics of nickel-based superalloys are reviewed with emphasis on the use of this class of materials within turbine engines. The role of major and minor alloying additions in multicomponent commercial cast and wrought superalloys is discussed. Microstructural stability and phases observed during processing and in subsequent elevated-temperature ser...

........................................................................................................................ 1 Résumé .......................................................................................................................... 2 Acknowledgement ........................................................................................................ 4 Table of contents ....

A criterion for predicting the formation of freckles for Pb-Sn and Ni-base superalloys is evaluated using available experimental data. The criterion is based on a maximum value of the Rayleigh number, which indicates that the magnitude of buoyancy forces is largest with respect to the retarding frictional forces. The definition of the Rayleigh number involves a characteristic length scale. The ...