Search for dissertations about: "surface defects"

Showing result 11 - 15 of 391 swedish dissertations containing the words surface defects.

  2. 11. Electronic Structure Calculations of Point Defects in Semiconductors

    Author : Andreas Höglund; Susanne Mirbt; Alison Mainwood; Uppsala universitet; []
    Keywords : Physics; electronic structure calculations; point defects; semiconductor; formation energy; equilibrium solubility limit; thermodynamic equilibrium concentration; transfer levels; negative-U; 110 surface; diffusion; activation energy; solar cells; Fysik;

    Abstract : In this thesis point defects in semiconductors are studied by electronic structure calculations. Results are presented for the stability and equilibrium concentrations of native defects in GaP, InP, InAs, and InSb, for the entire range of doping conditions and stoichiometry. READ MORE

  4. 12. On the Characterization and Generation of Flow Marks on Polymeric Surfaces

    Author : Giovanna Iannuzzi; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tiger stripes; surface defects; rheological properties; injection moulding; polymer processing; flow marks;

    Abstract : Polymer-based materials are widely used in the automotive industry for producing vehicle parts, for instance car bumpers, dash boards etc. A common manufacturing process for such components is injection moulding. READ MORE

  5. 13. Microstructure and mechanical properties of Ti-6Al-4V welds produced with different processes

    Author : Sakari Tolvanen; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fatigue; welding; porosity; microstructure; defects; Ti-6Al-4V;

    Abstract : Titanium alloys are widely used for components in the fan and compressor sections of aeroengines mainly because of their superior strength-to-weight ratio. Large static compressor components can be manufactured by welding together smaller subcomponents, which has potential to provide benefits such as higher buy-to-fly ratio and improved performance of the components. READ MORE

  6. 14. Welding of Ti-6Al-4V: Influence of welding process and alloy composition on microstructure and properties

    Author : Sakari Tolvanen; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fatigue; microstructure; Ti-6Al-4V; porosity; welding; defects;

    Abstract : Titanium alloys are widely used for components in the fan and compressor sections of aeroengines mainly because of their superior strength-to-weight ratio. Large static compressor components can be manufactured by welding together smaller subcomponents, which has potential to provide benefits such as higher buy-to-fly ratio and improved performance of the components. READ MORE

  7. 15. Detection and classification of internal flaws in laser powder bed fusion: application of in-situ monitoring for quality control of Hastelloy X builds

    Author : Claudia de Andrade Schwerz; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; melt pool; productivity; flaw detection; nickel-based superalloy; powder bed fusion; lack of fusion; spatter; defects; Additive manufacturing; process monitoring; pores;

    Abstract : Additive manufacturing technologies, in particular laser powder bed fusion (LPBF), have received much attention in recent years due to their multiple advantages over traditional manufacturing. Yet, the usage of additively manufactured products is still quite limited, mainly due to two factors: the low repeatability, which is particularly relevant for applications where high performance is required from the materials, and the typically low productivity, particularly relevant for products with a substantial production volume. READ MORE