Sökning: "Wear transitions"

Hittade 5 avhandlingar innehållade orden Wear transitions.

  1. 1. On wear transitions in the wheel-rail contact

    Författare :Sundh Jon; Ulf Olofsson; Staffan Jacobsson; KTH; []
    Nyckelord :Wear transitions; Wheel; Rail; Wear regime; Wear mechanism; Mechanical engineering; Maskinteknik;

    Sammanfattning : Wear transitions in the wheel–rail contact are of increasing interest since the general trend in railway traffic is toward increased velocities and axle loads. Curving increases the risk of flanging, causing the contact to change from an almost pure rolling wheel tread–rail head contact to more of a sliding wheel flange–rail gauge contact on the high rail in curves. LÄS MER

  3. 2. Phase stability and defect structures in (Ti,Al)N hard coatings

    Författare :Katherine M. Calamba; Magnus Odén; Jean Pierson; Mats Johansson; Gregory Abadias; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This study highlights the role of nitrogen vacancies and defect structures in engineering hard coatings with enhanced phase stability and mechanical properties for high temperature applications. Titanium aluminum nitride (Ti,Al)N based materials in the form of thin coatings has remained as an outstanding choice for protection of metal cutting tools due to its superior oxidation resistance and high-temperature wear resistance. LÄS MER

  4. 3. Metastable Alumina from Theory: Bulk, Surface, and Growth of κ-Al2O3

    Författare :Carlo Ruberto; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; density-functional theory; structure; cutting tools; plane waves; first principles; stability; one-dimensional electron gas; DFT; Tasker s rules; ionic crystals; polar surfaces; adsorption; pseudopotentials; Pauling s rules; bonding; surface states; TiC; ceramic materials;

    Sammanfattning : Aluminas are materials of high technological importance that show a fascinating structural flexibility, with a large amount of different phases (alpha, gamma, eta, delta, kappa, chi, ...) and phase transitions at relatively high temperatures. LÄS MER

  5. 4. Laser cladded steel - microstructures and mechanical properties of relevance for railway applications

    Författare :Simon Niederhauser; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fe-Cr alloy; Carbon Steel; Microstructure; Internal Stresses; HAZ; Laser Cladding; Co-Cr alloy; Cracking Behaviour; Mechanical Properties; Low Cycle Fatigue;

    Sammanfattning : Owing to increased requirements like increased axle load for railway wheels and rails, new material have to be employed. However, these requirements are mostly surface related, which makes it appropriate to change only the surface layer while keeping the bulk unchanged. LÄS MER

  7. 5. Thermal residual stresses, hardness and microstructural characterisation of functionally graded WC-Co composites

    Författare :Cecilia Larsson; Linköpings universitet; []
    Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : Functionally graded materials (FGMs) incorporate gradual transitions in their microstructure and/or composition with distance. The gradients provide means to favourably engineer their thermomechanical properties by changing e.g., the local modulus, yield strength, state of residual stress etc. LÄS MER