Sökning: "Nb- rich Phases"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden Nb- rich Phases.

1. 1. Laser-Directed Energy Deposition : Influence of Process Parameters and Heat-Treatments

   Författare :Suhas Sreekanth; Joel Andersson; Shrikant V. Joshi; Högskolan Väst; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Directed Energy Deposition; Alloy 718; Process Parameters; Heat Treatments; Nb- rich Phases; Production Technology; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik;

   Sammanfattning : Laser-Directed Energy Deposition (L-DED), an Additive Manufacturing (AM) processused for the fabrication of parts in a layer-wise approach has displayed an immense potential over the last decade. The aerospace industry stands as the primary beneficiary due to the L-DED process capability to build near-net-shape components with minimal tooling and thereby producing minimum wastage because of reduced machining. LÄS MER

3. 2. Synthesis of Transition Metal Aluminides from Elemental Powder Mixtures

   Författare :Hossein Sina; Materialteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aluminides; Intermetallics; Powder Metallurgy; Reactive Sintering; Combustion Synthesis; Thermal Analysis; DSC; Onset temperature; Phase evolution; SEM; EDS; XRD;

   Sammanfattning : Structural components such as those used in gas turbines for energy conversion applications, are subjected to high loads at elevated temperatures. In order to ensure that the components survive under these conditions for a sufficiently long time, it is imperative to select materials with good high temperature properties like strength and corrosion resistance. LÄS MER

4. 3. Powder-metallurgical processing and phase separation in ternary transition metal carbides

   Författare :Taoran Ma; Joakim Odqvist; Peter Hedström; Hans-Olof Andren; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : Ternary transition metal cubic carbides have high hardness and are potential carbides in cemented carbide and cermet tools, as well as hard coatings used to improve metal cutting performance. In the present work, (Ti,Zr)C, (V,Nb)C, and (V,Ta)C ternary cubic carbides were synthesized using traditional powder-metallurgical methods. LÄS MER

5. 4. Hot Cracking and Grain Boundary Weaknesses of Nickel - Based Superalloys

   Författare :Joel Håkan Andersson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hot cracks; Notch rupture testing; Eutectic; Weldability; Varestraint testing; Grain boundary weaknesses; Superalloys;

   Sammanfattning : Abstract Grain boundary weaknesses of nickel-based superalloys not only materialize during service in the hot turbine engine sections but also during the weld manufacturing. The performance, in this respect, of the most commonly used alloys at Volvo Aero Corporation (VAC), 718 and the higher temperature capacity Waspaloy, are therefore the main subjects for this thesis. LÄS MER

7. 5. First-principles investigations of planar defects

   Författare :Song Lu; Levente Vitos; Graeme Ackland; KTH; []
   Nyckelord :;

   Sammanfattning : Two types of planar defects, phase interface and stacking fault, are addressed in thisthesis. The first-principles exact-muffin orbitals method in combination with thecoherent-potential approximation is the main density functional theory (DFT) toolfor our studies. LÄS MER