Now showing items 21-40 of 56

    • Elemental electron energy loss mapping of a precipitate in a multi-component aluminium alloy 

      Mørtsell, Eva Anne; Wenner, Sigurd; Longo, Paulo; Andersen, Sigmund Jarle; Marioara, Calin Daniel; Holmestad, Randi (Journal article, 2016)
      The elemental distribution of a precipitate cross section, situated in a lean Al-Mg-Si-Cu-Ag-Ge alloy, has been investigated in detail by electron energy loss spectroscopy (EELS) and aberration corrected high angle annular ...
    • Extra electron diffraction spots caused by fine precipitates formed at the early stage of aging in Al-Mg-X (X=Si, Ge, Zn)-Cu alloys 

      Matsuda, Kenji; Kawai, Akihiro; Watanabe, Katsumi; Seungwon, Lee; Marioara, Calin Daniel; Wenner, Sigurd; Nishimura, Katsuhiko; Matsuzaki, Teiichiro; Nunomura, Norio; Sato, Tatsuo; Holmestad, Randi; Ikeno, Susumu (Journal article; Peer reviewed, 2017)
      Age-hardenable Al-Mg-Si, Al-Mg-Ge, and Al-Zn-Mg alloys including Cu were investigated by transmission electron microscopy to understand extra diffraction spots that appear in their selected area electron diffraction patterns. ...
    • Filler metal distribution and processing stability in laser-arc hybrid welding of thick HSLA steel 

      Bunaziv, Ivan; Wenner, Sigurd; Ren, Xiaobo; Frostevarg, Jan; Kaplan, Alexander F.H.; Akselsen, Odd Magne (Journal article; Peer reviewed, 2020)
      Welds made by high power laser beam have deep and narrow geometry. Addition offiller wire by the arc source,forming the laser-arc hybrid welding (LAHW) process, is very important to obtain required mechanical prop-erties. ...
    • 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 ...
    • Grain boundary structures and their correlation with intergranular corrosion in an extruded Al-Mg-Si-Cu alloy 

      Lervik, Adrian; Wenner, Sigurd; Lunder, Otto; Marioara, Calin Daniel; Holmestad, Randi (Peer reviewed; Journal article, 2020)
      A detailed analysis of grain boundaries in a highly textured Al-Mg-Si-Cu alloy is presented in this work. Electron backscatter diffraction demonstrates the presence of three main categories of grain boundaries in addition ...
    • How calcium prevents precipitation hardening in Al–Mg–Si alloys 

      Wenner, Sigurd; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Holmestad, Randi (Journal article, 2013)
      We have investigated the effect on precipitate microstructure and hardness upon adding small amounts of Ca to a base Al–Mg–Si alloy. The main investigative techniques were transmission and scanning electron microscopy. We ...
    • In situ DSC investigation into the kinetics and microstructure of dispersoid formation in Al-Mn-Fe-Si(-Mg) alloys 

      Kemsies, Richard H; Milkereit, Benjamin; Wenner, Sigurd; Holmestad, Randi; Kessler, Olaf (Journal article; Peer reviewed, 2018)
      Dispersoid strengthening in Al-Mn-Fe-Si(-Mg) aluminum wrought alloys can play an important role in applications at elevated temperatures. Fine and evenly distributed dispersoids are needed to increase alloy strength, which ...
    • In situ heating TEM observations of evolving nanoscale Al‐Mg‐Si‐Cu precipitates 

      Sunde, Jonas Kristoffer; Wenner, Sigurd; Holmestad, Randi (Journal article; Peer reviewed, 2019)
      This research concerns the precipitation and subsequent dissolution of precipitate phases in an Al–0.86Mg–0.62Si–0.1Cu (at.%) alloy subjected to varying thermal exposure during an in situ heating transmission electron ...
    • Mapping the chemistry within, and the strain around, Al-alloy precipitates at atomic resolution by multi-frame scanning transmission electron microscopy 

      Jones, Lewys; Wenner, Sigurd; Nord, Magnus Kristofer; Ninive, Per Harald; Løvvik, Ole Martin; Marioara, Calin Daniel; Holmestad, Randi; Nellist, Peter (Journal article; Peer reviewed, 2017)
      Al-Mg-Si(-Cu)alloys, used primarily in the transportation sector, are strengthened by nano-sized precipitate particles. There is a plethora of possible phases, depending onwhich elements are added to the alloy ...
    • Muon kinetics in heat treated Al (–Mg)(–Si) alloys 

      Wenner, Sigurd; Nishimura, Katsuhiko; Matsuda, Kenji; Matsuzaki, Teiichiro; Tomono, Dai; Pratt, Francis L.; Marioara, Calin Daniel; Holmestad, Randi (Journal article, 2013)
      Al–Mg–Si alloys are heat-treatable and rely on precipitation hardening for their mechanical strength. We have employed the technique of muon spin relaxation to further our understanding of the complex precipitation sequence ...
    • Muon Spin Relaxation Study of Solute–Vacancy Interactions During Natural Aging of Al-Mg-Si-Cu Alloys 

      Wenner, Sigurd; Marioara, Calin Daniel; Nishimura, Katsuhiko; Matsuda, Kenji; Lee, Seungwon; Namiki, Takahiro; Watanabe, Isao; Matsuzaki, Teiichiro; Holmestad, Randi (Journal article; Peer reviewed, 2019)
      Muon spin relaxation has the unique ability to detect very low concentrations of vacancies and vacancy–solute complexes in solids. In this work, we investigate quaternary Al-Mg-Si-Cu alloys and show that after quenching ...
    • Nanoscale modelling of combined isotropic and kinematic hardening of 6000 series aluminium alloys 

      Myhr, Ole Runar; Børvik, Tore; Marioara, Calin Daniel; Wenner, Sigurd; Hopperstad, Odd Sture (Peer reviewed; Journal article, 2020)
      Kinematic hardening is incorporated into a nanoscale model for 6000 series aluminium alloys consisting of three sub-models describing in turn precipitation of hardening particles, yield strength and work hardening. The ...
    • On the formation mechanism of Ba0.85Ca0.15Zr0.1Ti0.15O3 thin films by aqueous chemical solution deposition 

      Khomyakova, Evgeniya; Wenner, Sigurd; Bakken, Kristine; Schultheiß, Jan; Grande, Tor; Glaum, Julia; Einarsrud, Mari-Ann (Journal article; Peer reviewed, 2020)
      Here we report on the development of an environmentally friendly, simple and robust aqueous chemical solution route for the fabrication of Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) thin films. Using a stable aqueous precursor solution, ...
    • Optimising multi-frame ADF-STEM for high-precision atomic-resolution strain mapping 

      Jones, Lewys; Wenner, Sigurd; Nord, Magnus Kristofer; Ninive, Per Harald; Løvvik, Ole Martin; Holmestad, Randi; Nellist, P.D. (Journal article; Peer reviewed, 2017)
      Annular dark-field scanning transmission electron microscopy is a powerful tool to study crystal defects at the atomic scale but historically single slow-scanned frames have been plagued by low-frequency scanning-distortions ...
    • Phase stabilization principle and precipitate-host lattice influences for Al-Mg-Si-Cu alloy precipitates 

      Ehlers, Flemming J H; Wenner, Sigurd; Andersen, Sigmund Jarle; Marioara, Calin Daniel; Lefebvre, Williams; Boothroyd, Chris; Holmestad, Randi (Journal article, 2014)
      In this work, we seek to elucidate a common stabilization principle for the metastable and equilibrium phases of the Al–Mg–Si–Cu alloy system, through combined experimental and theoretical studies. We examine the structurally ...
    • Precipitate statistics in an Al-Mg-Si-Cu alloy from scanning precession electron diffraction data 

      Sunde, Jonas Kristoffer; Paulsen, Øyvind; Wenner, Sigurd; Holmestad, Randi (Journal article; Peer reviewed, 2017)
      The key microstructural feature providing strength to age-hardenable Al alloys is nanoscale precipitates. Alloy development requires a reliable statistical assessment of these precipitates, in order to link the microstructure ...
    • Precipitates in aluminium alloys 

      Andersen, Sigmund Jarle; Marioara, Calin Daniel; Friis, Jesper; Wenner, Sigurd; Holmestad, Randi (Journal article; Peer reviewed, 2018)
      Precipitation strengthening is a highly complex phenomenon on the nanoscale, responsible for providing strength in Al-Cu, Al-Mg-Cu, Al-Mg-Zn and Al-Mg-Si alloys. Advances in methodology, especially high-angle annular ...
    • Precipitation behavior in an Al-Cu-Mg-Si alloy during ageing 

      Gazizov, Marat; Marioara, Calin Daniel; Friis, Jesper; Wenner, Sigurd; Holmestad, Randi; Kaibyshev, Rustam (Peer reviewed; Journal article, 2019)
      The precipitation behavior and aging response of an Al-4.9Cu-0.74Mg-0.51Si-0.48Mn-0.1Cr-0.08Ti-0.02Fe (wt. %) alloy was examined in detail after aging at 170 °C with different dwell times up to 96 h. Deformation by ...
    • Precipitation behavior in an Al-Cu-Mg-Si alloy during ageing 

      Gazizov, Marat; Marioara, Calin Daniel; Friis, Jesper; Wenner, Sigurd; Holmestad, Randi; Kaibyshev, Rustam (Peer reviewed; Journal article, 2019)
      The precipitation behavior and aging response of an Al-4.9Cu-0.74Mg-0.51Si-0.48Mn-0.1Cr-0.08Ti-0.02Fe (wt. %) alloy was examined in detail after aging at 170 °C with different dwell times up to 96 h. Deformation by ...
    • Precipitation in a mixed Al-Cu-Mg/Al-Zn-Mg alloy system 

      Wenner, Sigurd; Friis, Jesper; Marioara, Calin Daniel; Holmestad, Randi (Journal article, 2016)
      The precipitation-hardened alloy systems Al–Cu–Mg (2xxx) and Al–Zn–Mg (7xxx) were compositionally combined from a base alloy containing 2% Cu and 1% Mg, added 1–4% Zn (weight fractions). Precipitates in these alloys were ...