Blar i NTNU Open på forfatter "Frafjord, Jonas"

Viser treff 1-7 av 7

    • Atomistic Scale Modelling of Defects in Aluminium Alloys 

      Frafjord, Jonas (Doctoral theses at NTNU;2020:400, Doctoral thesis, 2020)
      «Deformasjoner som en ser når metall bøyer seg, er en kollektiv bevegelse av små linjedefekter i atomstrukturen.» Dette sitatet oppsummerer temaet til doktorgradsarbeidet som handler om hvordan atomer i aluminium oppfører ...

    • First principle calculations of pressure dependent yielding in solute strengthened aluminium alloys 

      Frafjord, Jonas; Ringdalen, Inga Gudem; Hopperstad, Odd Sture; Holmestad, Randi; Friis, Jesper (Journal article; Peer reviewed, 2020)
      The pressure dependence of the yield stress in solute strengthened aluminium alloys is investigated by first principle calculations. The solute elements studied are magnesium, silicon and copper. A fixed boundary cluster ...

    • Fully resolved strain field of the β’’ precipitate calculated by density functional theory 

      Frafjord, Jonas; Dumoulin, Stephane; Wenner, Sigurd; Ringdalen, Inga Gudem; Holmestad, Randi; Friis, Jesper (Peer reviewed; Journal article, 2020)
      The β′′ precipitate is the main hardening phase in age hardenable Al-Mg-Si alloys, and it is therefore of major scientific and industrial importance. A full model of the β′′ precipitate cross-section embedded in an aluminium ...

    • On the Atomic Structure of the β′′ Precipitate by Density Functional Theory 

      Frafjord, Jonas; Ringdalen, Inga Gudem; Holmestad, Randi; Friis, Jesper (Peer reviewed; Journal article, 2023)
      The substitution of elements into the precipitate in the 6xxx-series of aluminium alloys is an interface sensitive problem. The strain caused by the misfit between the precipitate and the matrix interacts with the size ...

    • Scanning precession electron diffraction data analysis approaches for phase mapping of precipitates in aluminium alloys 

      Thronsen, Elisabeth; Bergh, Tina; Thorsen, Tor Inge; Christiansen, Emil; Frafjord, Jonas; Crout, Philip; Van Helvoort, Antonius Theodorus Johannes; Midgley, Paul A.; Holmestad, Randi (Peer reviewed; Journal article, 2023)
      Mapping the spatial distribution of crystal phases with nm-scale spatial resolution is an important characterisation task in studies of multi-phase materials. One popular approach is to use scanning precession electron ...

    • Studying GPI zones in Al-Zn-Mg alloys by 4D-STEM 

      Thronsen, Elisabeth; Frafjord, Jonas; Friis, Jesper; Marioara, Calin Daniel; Wenner, Sigurd; Andersen, Sigmund Jarle; Holmestad, Randi (Journal article; Peer reviewed, 2021)
      A new methodology has been developed to study the fine details of GP zones in age-hardenable aluminium alloys. It is complementary to atomic resolution high-angle annular dark-field scanning transmission electron microscopy ...

    • The Vacuum Polarisation Contribution to the Lamb Shift Using Non-Relativistic Quantum Electrodynamics 

      Frafjord, Jonas (Master thesis, 2016)
      In this thesis we calculate the vacuum polarisation contribution to the well-known Lamb shift. The Lamb shift is a correction of order $\alpha^5$ to the non-relativistic energy spectrum of the hydrogen atom. We discuss the ...