Browsing by Subject "stopy niklu"

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Analiza procesów wydzielania w stopie Ni-Mo-Cr podczas wysokotemperaturowego wyżarzania
(Data obrony: 2020-12-11) Maliszewski, Tomasz
Wydział Inżynierii Metali i Informatyki Przemysłowej
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Charakterystyka mikrostruktury i właściwości nadstopu IN738 po napawaniu łukowym
(Data obrony: 2020-01-22) Wojciechowski, Przemysław
Wydział Inżynierii Metali i Informatyki Przemysłowej
Access status: Open Access ,
Hot cracking of nickel-based superalloy turbine blade
(2015) Rakoczy, Łukasz; Tuz, Lechosław; Pańcikiewicz, Krzysztof
The aim of this study was to present the hot cracking behavior of a blade originating from a turbine blade segment. The crack was induced by a gas tungsten arc welding process, and the research material was a MAR-M247 nickel based superalloy. This alloy is considered to be difficult to weld because of its high tendency to crack. Light microscopy and scanning electron microscopy show the occurrence of cracking in the melted zone, heat-affected zone, and base alloy. A scanning electron microscopy investigation revealed that cracks are propagated by stresses and liquation of the low temperature constituent.
Access status: Open Access ,
Microstructure evaluation of laser-welded 600 nickel alloy
(Wydawnictwa AGH, 2016) Tuz, Lechosław
This paper presents the results of a microstructure analysis of a laser butt-welded 600 nickel alloy. A microstructure evaluation of the joint is carried out with the use of light microscopy and scan- ning electron microscopy. The results indicate a phase γ with some particles in the grain boundaries in the base metal. In the weld, a cellular-dendritic structure was observed.
Access status: Open Access ,
Microstructure stability of second and fourth generation single crystal nickel-base superalloys during high temperature creep deformation
(Data obrony: 2011) Ziętara, Maciej
Wydział Inżynierii Metali i Informatyki Przemysłowej
Single crystal (SC) nickel-base superalloys have been developed over the past 40 years especially for modern gas turbine applications. Their introduction into commercial use as turbine blades in aero-engines is regarded as one of the most significant technological achievements of the past two decades [1], This group of alloys have superior mechanical properties such as creep resistance and high temperature strength. They are hardened by a high volume fraction of the ordered γ' phase, which is coherently precipitated in the $\gamma$ matrix. These materials are mainly applied as turbine blades and vanes in aero-engines and industrial gas turbines. Turbine blades operate at high temperature under a centrifugal force causing creep deformation of the material, which leads to so-called rafting (i.e. directional coarsening). A characteristic microstructural property of SC superalloys is the ability of cubic $\gamma^{‘}$ phase particles to transform under the influence of stress and temperature into the plates (rafts). The rafts develop in the early stages of creep at high temperature (about $1000^{\circ}C$) and low stress (about 100 MPa). Rafting appears to be an essential factor determining creep strength of nickel-base single crystal superalloys at high temperature and influencing their applications [2]. A new, 4th generation single crystal superalloy has been jointly developed by GE Aircraft Engines (GEAE), Pratt & Whitney (P&W) and NASA. The focus of the effort was to develop a turbine airfoil alloy with long- term durability for use in the High Speed Civil Transport. In order to achieve adequate long time strength improvements at moderate temperature and to retain good microstructure stability, it was necessary to make significant composition changes from 2nd and 3rd generation single crystal superalloys. These include lower chromium levels, higher cobalt and rhenium levels and the addition of a new alloying element, ruthenium. The new superalloy is known as MX4 at GEAE and PWA 1497 at P&W [3]. In the present study, a detailed investigation of two nickel-base single crystal superalloys, 2nd generation PWA 1484 and 4th generation PWA 1497, was performed in order to estimate stereologically their microstructure evolution and stability during ageing and creep deformation at high temperature.
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Mikrostruktura i wybrane własności przykładowej odkuwki ze stopu Waspaloy
(Data obrony: 2020-07-13) Sromek, Marek
Wydział Inżynierii Metali i Informatyki Przemysłowej
Access status: Open Access ,
Przyczyny powstawania niedolewów w supercienkościennych elementach odlewanych z nadstopów na osnowie niklu
(Data obrony: 2010) Cygan, Rafał
Wydział Odlewnictwa
The research described in this doctoral thesis is a result of a wider project aimed at the description of physical and chemical phenomena occurring at the metal – ceramic mold and ceramic mold – environment boundary during the casting and solidification of investment castings (Research and development project R15 008 03 realized by the AGH in Cracow 2007 – 2010). The physical and chemical phenomena occurring at the metal-ceramic mold interface during the pouring of liquid metal into the mold influence the casting process significantly, and can constitute one of the main reasons for the forming of defects, including misruns and nonfills. In order to efficiently model and, as a result, optimize those technological processes, a series of experiments aimed at the investigation of metal-mold interface phenomena was conducted. The phenomenon of wetting of ceramic materials by liquid metals plays a major role in technological processes involving ceramics and liquid phase. The characteristic used most often to describe the degree of ceramic wetting by a liquid metal is the wetting angle $\theta$. The thermal and physical properties of shelling (molding) materials have a decisive influence on the structure and properties of a casting. That is so because they have the decisive influence on the thermal exchange processes between the casting and the ceramic mold. The exact importance of such properties can be especially appreciated when performing computer simulations of the casting solidification and cooling processes. The solidification process creates the original, primary structure, and the cooling of an already solidified casting creates the final structure of the casting alloy. The course of these processes, which decides about the obtained structure and properties of the casting, is largely dependant on the rate, at which the heat is being removed from the solidifying alloy. Very complicated geometries (super-thin sectioned castings with turbine blade sections measuring at times as little as 0,2 mm), less than perfect casting properties of superalloys and very strict quality standards contribute to the fact, that scrap rates for such castings can be very high. The purpose of a comparison between computer simulations and real-life experiments was to define the preliminary basic physical and chemical parameters, such as the thermal conductivity coefficient between the ceramic mold and insulation or between the ceramic mold and the environment; as well as to perform an initial verification of the ProCast simulation suite ceramic and thermally insulating materials database.
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Wpływ modyfikacji składu chemicznego na mikrostrukturę stopu Haynes 282 po obróbce cieplnej
(Data obrony: 2019-01-30) Janeczek, Kinga
Wydział Metali Nieżelaznych