Search for dissertations about: "Twinning"

Showing result 16 - 20 of 42 swedish dissertations containing the word Twinning.

  2. 16. Open-Framework Germanates : Crystallography, structures and cluster building units

    Author : Kirsten Elvira Christensen; Xiaodong Zou; Osamu Terasaki; Angeles Monge; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; germanate; crystallography; building unit; zeotype; scale chemistry; Chemistry; Kemi; strukturkemi; Structural Chemistry;

    Abstract : This thesis is focussing on the crystallographic challenges and what knowledge we can gain from studying the different open-framework germanates. Five new open-framework germanates have been synthesized and the structures have been determined by single crystal X-ray diffraction. READ MORE

  4. 17. Defects in Austenitic Steels and Hard Metals - A DFT-based Study

    Author : Ruiwen Xie; Levente Vitos; Ilja Turek; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; defects; austenitic steels; cemented carbides; ab-initio; Teknisk materialvetenskap; Materials Science and Engineering;

    Abstract : Materials are never 100% pure due to the limitation of purification method or manufacturing process. Nor are they perfect, especially under deformation. The present work aims to explore different roles played by the defects in austenitic steels and hard metals. READ MORE

  5. 18. Carbon Effect on Mechanical Properties in Austenitic Steels - A DFT-based Study

    Author : Ruiwen Xie; Levente Vitos; Pär Olsson; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Teknisk materialvetenskap; Materials Science and Engineering;

    Abstract : To study the effect of carbon interstitials in austenitic steels on plastic deformation mechanisms is the main goal of the present thesis. Using first-principlesmethods, the generalized stacking fault energy (GSFE) of C-alloyed γ-Fe is firstcalculated. The GSFE curve includes several prominent stacking fault energiesthat are fundamental for, e. READ MORE

  6. 19. First-principles description of planar faults in metals and alloys

    Author : Wei Li; Vitos Levente; Göran Wahnström; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : Phase interface and stacking fault are two common planar defects in metallic materials. In the present thesis, the interfacial energy and the generalized stacking fault energy of random alloys are investigated using density functional theory formulated within the exact muffin-tin orbitals (EMTO) method in combination with the coherent-potential approximation (CPA). READ MORE

  7. 20. Microstructural Evolution In As-cast Alloys during Plastic Deformation

    Author : Mitra Basirat; Pär Jönsson; Hasse Fredriksson; Jacques Lacaze; KTH; []
    Keywords : plastic deformation; compression test; recrystallization; deformation band; As-cast; microsegregation; carbide dissolution; disordered structure; order disorder transformation; twining; steel; β brass; copper; SRA - E-Science SeRC ; SRA - E-vetenskap SeRC ;

    Abstract : The effect of deformation on microstructural changes in metals and alloys is the subject of considerable practical interest. The ultimate goal is to control, improve and optimize the microstructure and texture of the finished products produced by metal forming operations. READ MORE