Sökning: "grain boundaries"

Visar resultat 16 - 20 av 199 avhandlingar innehållade orden grain boundaries.

  1. 16. Grain Morphology and Intergranular Structure of Si3N4 and Al2O3 Based Ceramics

    Författare :Håkan Björklund; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; whiskers; stereology; electron microscopy; sintering; silicon nitride; quantitative microscopy; grain growth; ceramics; microstructure; aluminium oxide;

    Sammanfattning : This thesis concerns factors controlling the grain morphology in Si3N4 and Al2O3 based ceramics. The microstructures of the ceramics were characterized by scanning electron microscopy in combination with quantitative microscopy and stereologic methods. LÄS MER

  3. 17. Grain Size and Solid Solution Strengthening in Metals

    Författare :Dilip Chandrasekaran; KTH; []
    Nyckelord :strengthening mechanisms; flow stress; solid solution strengthening; grain size strengthening; micromechanical modelling; AFM; EBSD;

    Sammanfattning : The understanding of the strengthening mechanisms is crucialboth in the development of new materials with improvedmechanical properties and in the development of better materialmodels in the simulation of industrial processes. The aim ofthis work has been to study different strengthening mechanismsfrom a fundamental point of view that enables the developmentof a general model for the flow stress. LÄS MER

  4. 18. Magnetic Bicrystal Junctions - a Study of Half-Metallic Manganite Grain Boundaries

    Författare :Robert Gunnarsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis presents studies on magnetic bicrystal junctions. In these, films on either side of the junction are structurally and magnetically misoriented. This type of device enables us to study junction magnetoresistance and spin polarized charge transport between ferromagnets with well defined directions of magnetization. LÄS MER

  5. 19. 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. 20. Atom Probe Tomography of Hydrogen and of Grain Boundaries in Corroded Zircaloy-2

    Författare :Gustav Sundell; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; corrosion; Field adsorption.; Hydrogen pick-up; Hydrogen analysis; Zirconium alloys; Atom probe tomography;

    Sammanfattning : Due to their low thermal neutron capture cross-section, zirconium alloys are widely used in the nuclear industry for fuel cladding and structural components. The lifetime of the fuel assemblies in the reactors are largely dictated by the ability of the fuel cladding to withstand corrosion and mechanical damage. LÄS MER