Sökning: "subsurface defects"

Hittade 5 avhandlingar innehållade orden subsurface defects.

  1. 1. Additive manufacturing of Ni-based Superalloys- an analysis of parameter and strategy driven properties in Electron Beam Melting Process

    Författare :Xiaoyu Zhao; Amir Rashid; Carolin Körner; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Additive manufacturing; Electron beam melting; Super-alloys; process optimization; surface defects; subsurface defects; mechanical properties; thermal stresses; thermal deformation; Production Engineering; Industriell produktion;

    Sammanfattning : Metal AM processes produce significantly rough surfaces as compared to wrought or machined components. Currently, the as-EBM surfaces are extremely rough and consequently, the as-built components could not be directly used as commercial products. The state-of-the-art research has focused primarily on deeply machined (DM) samples. LÄS MER

  3. 2. Wheels, Rails and Insulated Joints - Damage and Failure Probability at High Speed and Axle Load

    Författare :Johan Sandström; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail breaks; probability; railway mechanics; contact mechanics; insulated joints; defects; fatigue;

    Sammanfattning : The thesis deals with some fatigue related problems in railway mechanics related to increased axle loads and speeds. The focus is on defects and discontinuities in the wheel--rail system that affect the risk of fatigue and fracture of railway components such as wheels, rails and insulated joints. LÄS MER

  4. 3. Machinability of Single-phase Materials : Surface integrity and tool wear analysis

    Författare :Mike Olsson; Industriell Produktion; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Machinability; Niobium; Tungsten; Oxygen-free copper; Surface integrity; Tool wear;

    Sammanfattning : The quality and performance of products are particularly important in sectors such as research facilities and in the nuclear, military and space industries. These sectors make use of high-performance materials that are uncommon in other contexts and therefore place high requirements on personnel, machines and tools. LÄS MER

  5. 4. Chemistry and Physics of Cu and H2O on ZnO Surfaces : Electron Transfer, Surface Triangles, and Theory

    Författare :Matti Hellström; Kersti Hermansson; Peter Broqvist; Daniel Spångbeg; Jörg Behler; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; catalysis; density functional theory; SCC-DFTB; band-filling correction;

    Sammanfattning : This thesis discusses the chemistry and physics of Cu and H2O on ZnO surfaces, based primarily on results from quantum chemical calculations. The underlying context is heterogeneous catalysis, where Cu/ZnO-mixtures are used in the industrial synthesis of methanol and in the water gas shift reaction. LÄS MER

  7. 5. Numerical modelling of the rock fracture process under mechanical loading

    Författare :Hongyuan Liu; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mining and Rock Engineering; Gruv- och Berganläggningsteknik;

    Sammanfattning : The fracture of rock has been the subject of the extensive research in the mechanical fragmentation. With the rapid development of computing power, interactive computer graphics and topological data structure, numerical tool has become a good tool to gain some insights into the problem of rock fracture. LÄS MER