Sökning: "dislokationer"

Visar resultat 1 - 5 av 13 avhandlingar innehållade ordet dislokationer.

  1. 1. Microstructural Decay in High-Strength Bearing Steels under Rolling Contact Fatigue

    Författare :Tania Loaiza; Peter Hedström; Mårten Olsson; Steve Ooi; Prasath Babu; Harry Bhadeshia; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microstructural decay; microscopy; rolling contact fatigue; Hybrid 60 steel; Bearing steel; 52100; dislocations; ferrite microbands; Mikrostrukturell nedbrytning; mikroskopi; rullande kontaktfatigue; Hybrid 60-stål; dislokationer; Materials Science and Engineering; Teknisk materialvetenskap;

    Sammanfattning : The work presented in this thesis aims to enhance our understanding of material decay in high-strength steels used for bearing applications. The primary objective is to investigate the microstructural changes in two high-strength steels: 52100 steels, a popular bearing steel, and Hybrid 60, a relatively new bearing steel designed for long fatigue life and use at elevated temperatures. LÄS MER

  3. 2. As-cast AZ91D magnesium alloy properties : Effects of microstructure and temperature

    Författare :Hoda Dini; Anders E.W. Jarfors; Nils-Eric Andersson; Jönköping University; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Magnesium; Magnesium Alloy; AZ91D; High-Pressure Die-Casting; Mechanical Property; Microstructural Characterisation; Physical Modelling; Dislocations; Distortion; Residual Stress; Magnesium; Magnesiumlegering; AZ91D; Pressgjutna; Mekanisk Egenskap; Mikrostrukturkarakterisering; Fysikalisk Modellering; Flytspänning; Dislokationer; Geometrisk Tolerans; Restspänning;

    Sammanfattning : Today, there is an essential need for lightweight, energy-efficient, environmentally benign engineering systems, and this is the driving force behind the development of a wide range of structural and functional materials for energy generation, energy storage, propulsion, and transportation. These challenges have motivated the use of magnesium alloys for lightweight structural systems. LÄS MER

  4. 3. Modelling and simulation of short fatigue cracks

    Författare :Christina Bjerkén; Materialteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; materialteknik; Materiallära; Material technology; Interface cracks; Dislocations; Short cracks; Local plasticity;

    Sammanfattning : The growth of short fatigue cracks deviates from the behaviour of long fatigue cracks even if subjected to the same nominal driving force. The influence from the microstructure is pronounced, while crack closure effects may not be that important as for longer cracks. LÄS MER

  5. 4. Creep modeling and first-principles investigation of high-temperature alloys

    Författare :Jing Zhang; Pavel A. Korzhavyi; Rolf Sandström; Gunther Eggeler; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Austenitic stainless steels; Nickel-based superalloys; Fundamental creep models; EMTO-CPA method; Quasi-harmonic Debye model; Thermo-mechanical properties; High temperatures.; Teknisk materialvetenskap; Materials Science and Engineering;

    Sammanfattning : Stainless steels and nickel-based superalloys are materials that have been widely used to manufacture components servicing at high temperatures. Creep strength is one of the most important properties in such conditions. LÄS MER

  7. 5. Epitaxy of group III-nitride materials using different nucleation schemes

    Författare :Rosalia Delgado Carrascon; Vanya Darakchieva; Daniela Gogova; Alice Hospodková; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Group III-nitride materials, gallium nitride (GaN), aluminum nitride (AlN) and indium nitride (InN) have direct band gaps with band gap energies ranging from the infrared (InN) to the ultraviolet (GaN) and to the deep ultraviolet (AlN) wave-lengths, covering the entire spectral range from 0.7 eV to 6.2 eV upon alloying. LÄS MER