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Showing result 1 - 5 of 124 swedish dissertations matching the above criteria.

  2. 1. Transition Metal Nitrides : Alloy Design and Surface Transport Properties using Ab-initio and Classical Computational Methods

    Author : Davide G. Sangiovanni; Valeriu Chirita; Lars Hultman; Paul Mayrhofer; Linköpings universitet; []
    Keywords : ;

    Abstract : Enhanced toughness in brittle ceramic materials, such as transition metal nitrides (TMN), is achieved by optimizing the occupancy of shear-sensitive metallic electronic-states. This is the major result of my theoretical research, aimed to solve an inherent long-standing problem for hard ceramic protective coatings: brittleness. READ MORE

  4. 2. Influence of carbides and nitrides on corrosion initiation of advanced alloys : A local probing study

    Author : Eleonora Bettini; Jinshan Pan; Thomas Ladwein; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; carbides; nitrides; microstructure; CoCrMo alloys; duplex stainless steels; localized corrosion; transpassive dissoluti on; elemental depletion; AFM; TEM; SEM.;

    Abstract : Advanced alloys often present precipitated carbides and nitrides in their microstructure following exposure to elevated temperatures. These secondary phases are usually undesirable, because potentially deleterious for the corrosion and mechanical performances of the material. READ MORE

  5. 3. Toughness enhancement in transition metal nitrides

    Author : Davide Giuseppe Sangiovanni; Valeriu Chirita; Lars Hultman; Sergey Simak; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; cubic; transition metal nitrides; mechanical properties; ab initio; dft; toughness; ductility; electronic structure; Condensed matter physics; Kondenserade materiens fysik;

    Abstract : Toughness enhancements can be induced in cubic-B1 transition metal nitride alloys by an increased occupation of the d-t2g metallic states. In this Licentiate Thesis I use density functional theory to investigate the mechanical properties of TiN and VN and of the ternaries obtained by replacing 50% of Ti and V atoms with M (M = V, Nb, Ta, Mo, and W) to form ordered structures with minimum number of inter-metallic bonds. READ MORE

  6. 4. Configurational and Magnetic Interactions in Multicomponent Systems

    Author : Björn Alling; Igor A. Abrikosov; Lars Hultman; Stefan Blügel; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Magnetic interactions; Configurational thermodynamics; Curie temperature; theoretical physics; magnetism; TiAlN; TiN; AlN; CrN; TiCrN; nitrides; NiMnSb; NiCuMnSb; Heusler alloys; spintronics; half-metallic; spinodal decomposition; first-principles; ab-initio; Magnetism; Magnetism;

    Abstract : This thesis is a theoretical study of configurational and magnetic interactions in multicomponent solids. These interactions are the projections onto the configurational and magnetic degrees of freedom of the underlying electronic quantum mechanical system, and can be used to model, explain and predict the properties of materials. READ MORE

  7. 5. Refractory High-entropy Alloy and Nitride Thin Films

    Author : Rui Shu; Per Eklund; Arnaud Le Febvrier; Alfred Ludwig; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; High-entropy alloy; nitrides; magnetron sputtering; superconductor; irradiation-tolerance; protective coating.;

    Abstract : This thesis focuses on understanding the process-structure-property relation-ships for several refractory-metal-based high-entropy alloys and nitrides synthesized by magnetron sputtering.  The thesis begins with the growth of TiZrNbTaNx understoichiometric nitrides by controlling substrate temperature and nitrogen flow ratio fN. READ MORE