Sökning: "yt- och materialvetenskap"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden yt- och materialvetenskap.

  1. 1. Comprehensive numerical analysis of stress state in adhesive layer of joint including thermal residual stress and material non-linearity

    Författare :Nawres Jabar Al-Ramahi; Roberts Joffe; Janis Varna; Lars Mikkelsen; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Single-lap adhesive joint; Double-lap adhesive joint; Unbalanced bi-material DCB; Residual thermal stresses; Finite element method; Crack path; Crack closure; Polymeric Composite Materials; Polymera kompositmaterial;

    Sammanfattning : The main objective of this work is to improve understanding of the stress state in the adhesive layer of bonded joints and identify key parameters which govern performance of adhesive joints. This information is crucial for the prediction of the failure initiation and propagation with the further estimation of the durability and strength of adhesively bonded structures. LÄS MER

  3. 2. Effect of Stress Relief Annealing: Part Distortion, Mechanical Properties, and Microstructure of Additively Manufactured Austenitic Stainless Steel

    Författare :Emil Edin; Marta-Lena Antti; Pia Åkerfeldt; Fredrik Svahn; Magnus Neikter; Paul Åkerström; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laser powder bed fusion; stainless steel; residual stress; heat treatment; tensile testing; relaxation testing; Materialteknik; Engineering Materials;

    Sammanfattning : Additive manufacturing (AM) processes may introduce large residual stresses in the as-built part, in particular the laser powder bed fusion process (L-PBF). The residual stress state is an inherent consequence of the heterogeneous heating and subsequent cooling during the process. LÄS MER

  4. 3. Galling of high strength steels and stainless steels in sheet metal forming as evaluated using pin-on-disc testing

    Författare :Jenny Eriksson; Mikael Olsson; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Galling; sheet metal forming; high strength steels; stainless steels; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

    Sammanfattning : The thesis focuses on the problem galling in sheet metal forming operations. Galling occurs when sheet metal transfers from the sheet surface onto the tool surface and causes surface damages to following sheets in the forming operation. When this happens the tool must be replaced causing production stops and additional expenses. LÄS MER

  5. 4. Additive Manufacturing of Ni-Fe Superalloys : Exploring the Alloying Envelope and the Impact of Process on Mechanical Properties

    Författare :Carl Johan Hassila; Urban Wiklund; Staffan Jacobson; Johan Moverare; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Additive manufacturing; alloying for AM; PBF-LB; microstructure; tensile and impact testing; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

    Sammanfattning : Additive manufacturing of metals has received a lot of attention in the last decade as this family of manufacturing processes allows the manufacturing of complicated geometries which would be difficult to produce using conventional manufacturing techniques. Additive manufacturing of the Ni-Fe based superalloys 625 and 718 using the Powder Bed Fusion – Laser Beam (PBF-LB) process is facilitated by the fact that these alloys were developed as weldable alternatives to other high-strength, high-temperature Ni-based superalloys. LÄS MER

  7. 5. Tribology in Metal Working

    Författare :Maria Nilsson; Staffan Jacobson; Mikael Olsson; Magnus Jarl; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tribology; friction; wear; metal working; coatings; wire drawing; hot work rolls; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials; Steel Forming and Surface Engineering;

    Sammanfattning : This thesis focuses on the tribological performance of tool surfaces in two steel working operations, namely wire drawing and hot rolling. In all forming operations dimensions and surface finish of the products are of utmost importance. LÄS MER