Browsing NTNU Open by Author "Marioara, Calin Daniel"

Now showing items 21-40 of 105

    • Clustering and Vacancy Behavior in High- and Low-Solute Al-Mg-Si Alloys 

      Wenner, Sigurd; Nishimura, Katsuhiko; Matsuda, Kenji; Matsuzaki, Teiichiro; Tomono, Dai; Pratt, Francis L.; Marioara, Calin Daniel; Holmestad, Randi (Journal article, 2014)
      The precipitate microstructure and vacancy distribution in Al-Mg-Si alloys with different amounts of solute and different heat treatments were investigated by transmission electron microscopy and muon spin relaxation ...

    • Copper enrichment on aluminium surfaces after electropolishing and its effect on electron imaging and diffraction 

      Wenner, Sigurd; Lervik, Adrian; Thronsen, Elisabeth; Marioara, Calin Daniel; Kubowicz, Stephan; Holmestad, Randi (Peer reviewed; Journal article, 2021)
      Electropolishing is the most common method of preparing samples of aluminium alloys for scanning and transmission electron microscopy, as it yields a good surface quality and large flat, electron-transparent areas. Like ...

    • Cu atoms suppress misfit dislocations at the β″/Al interface in Al-Mg-Si alloys 

      Saito, Takeshi; Ehlers, Flemming J H; Lefebvre, Williams; Hernandez-Maldonado, David; Bjørge, Ruben; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Mørtsell, Eva Anne; Holmestad, Randi (Journal article, 2016)
      The Cu interactions with the Al–Mg–Si alloy main hardening phase β″ are investigated in atomic scale, by using experimental and simulated high angle annular dark-field scanning transmission electron microscopy techniques ...

    • Data on atomic structures of precipitates in an Al-Mg-Cu alloy studied by high resolution transmission electron microscopy and first-principles calculations 

      Chen, Xuanliang; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Friis, Jesper; Lervik, Adrian; Holmestad, Randi; Kobayashi, Equo (Journal article; Peer reviewed, 2021)
      The dataset refers to the research article “Precipitation processes and structural evolutions of various GPB zones and two types of S phases in a cold-rolled Al-Mg-Cu alloy” [1]. Transmission electron microscopy (TEM) and ...

    • Deformation and strain localization in polycrystals with plastically heterogeneous grains 

      Khadyko, Mikhail; Marioara, Calin Daniel; Ringdalen, Inga Gudem; Dumoulin, Stephane; Hopperstad, Odd Sture (Journal article; Peer reviewed, 2016)
      A model of a polycrystalline material is studied, where each grain consists of several zones with different plastic properties. The size and configuration of the zones as well as their properties are mimicking the situation ...

    • Detailed investigation of the shearing mechanism of β" precipitates in Al-Mg-Si alloys 

      Christiansen, Emil; Marioara, Calin Daniel; Ringdalen, Inga Gudem; Bjørge, Ruben; Holmedal, Bjørn; Hopperstad, Odd Sture; Holmestad, Randi (Peer reviewed; Journal article, 2020)
      The mechanism behind shearing of β'' precipitates in Al-Mg-Si alloys during deformation is investigated by applying advanced transmission electron microscopy (TEM) techniques and frozen phonon multislice TEM image simulations ...

    • Directionality and column arrangement principles of precipitates in Al-Mg-Si-(Cu) and Al-Mg-Cu linked to line defect in Al 

      Andersen, Sigmund Jarle; Marioara, Calin Daniel; Friis, Jesper; Bjørge, Ruben; Du, Qiang; Ringdalen, Inga Gudem; Wenner, Sigurd; Mørtsell, Eva Anne; Holmestad, Randi; Saito, Takeshi; Røyset, Jostein; Reiso, Oddvin (Journal article, 2016)
      In the structures of all metastable precipitates in Al-Mg-Cu and Al-Mg-Si alloys, we find that column surrounding of an element column in the needle/lath direction order according to simple principles. Advanced transmission ...

    • Early combination of material characteristics and toxicology is useful in the design of low toxicity carbon nanofiber 

      Jensen, Ellen K; Larsen, Sten Yngve; Nygaard, Unni Cecilie; Marioara, Calin Daniel; Syversen, Tore (Journal article; Peer reviewed, 2012)
      This paper describes an approach for the early combination of material characterization and toxicology testing in order to design carbon nanofiber (CNF) with low toxicity. The aim was to investigate how the adjustment of ...

    • Edge interfaces of the Ω plates in a peak-aged Al-Cu-Mg-Ag alloy 

      Gazizov, Marat; Boev, A.O.; Marioara, Calin Daniel; Holmestad, Randi; Gazizova, M.Yu.; Kaibyshev, Rustam (Journal article; Peer reviewed, 2022)
      The coherent edge interface structures of the relatively thin {111}Al Ω plates have been analyzed in a peak-aged Al-Cu-Mg-Ag alloy by atomic-resolution scanning transmission electron microscopy (STEM). Analysis of STEM ...

    • Effect of Copper Addition on Precipitation Behavior near Grain Boundary in Al-Zn-Mg Alloy 

      Matsuda, Kenji; Yasumoto, Toru; Bendo, Artenis; Tsuchiya, Taiki; Lee, Seungwon; Nishimura, Katsuhiko; Nunomura, Norio; Marioara, Calin Daniel; Lervik, Adrian; Holmestad, Randi; Toda, Hiroyuki; Yamaguchi, Masatake; Ikeda, Ken-ichi; Homma, Tomoyuki; Ikeno, Susumu (Journal article; Peer reviewed, 2019)
      The effect of Cu-addition on age-hardening and precipitation have been investigated by hardness measurement, tensile test, high resolution transmission electron microscopy (HRTEM) and high angle annular dark field scanning ...

    • Effect of copper addition on the cluster formation behavior of Al-Mg-Si, Al-Zn-Mg, and Al-Mg-Ge in the natural aging 

      Hatakeyama, Daichi; Nishimura, Katsuhiko; Matsuda, Kenji; Namiki, Takahiro; Lee, Seungwon; Nunomura, Norio; Aida, Tetsuo; Matsuzaki, Teiichiro; Holmestad, Randi; Wenner, Sigurd; Marioara, Calin Daniel (Journal article; Peer reviewed, 2018)
      The time-dependent resistivity of Al-Mg-Si(-Cu), Al-Zn-Mg(-Cu), and Al-Mg-Ge(-Cu) alloys are studied over a range of constant temperatures between 255 K and 320 K. The resistivity vs time curves for the samples show three ...

    • Effect of copper on fine precipitates at the early stage of aging in Al-Mg-X (X=Si, Ge, Zn) alloys 

      Matsuda, Kenji; Kawai, Akihiro; Watanabe, Katsumi; Lee, Seungwon; Marioara, Calin Daniel; Wenner, Sigurd; Nishimura, Katsuhiko; Matsuzaki, Teiichiro; Nunomura, Norio; Sato, Tatsuo; Holmestad, Randi; Ikeno, Susumu (Journal article, 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. ...

    • Effect of cyclic ageing on the early-stage clustering in Al–Zn-Mg(-Cu) alloys 

      Shah, Sohail; Thronsen, Elisabeth; Hatzoglou, Constantinos; Wenner, Sigurd; Marioara, Calin Daniel; Holmestad, Randi; Holmedal, Bjørn (Peer reviewed; Journal article, 2022)
      The cyclic application of mechanical stress to aluminum alloys at room temperature, referred to as cyclic ageing, continuously injects vacancies, enabling dynamic precipitation of a fine distribution of solute clusters. ...

    • The Effect of Elevated Temperatures on Precipitation in Aluminium Alloys – An Advanced Transmission Electron Microscopy Study 

      Sunde, Jonas Kristoffer (Doctoral theses at NTNU, 2020:229, Doctoral thesis, 2020)
      Aluminium (Al) alloys are increasingly found and sought-after in applications that involve exposure to elevated temperatures. Examples are automotive components located in the engine room, heat exchangers, and subsea/offshore ...

    • Effect of low Cu addition and thermo-mechanical history on precipitation in Al-Mg-Si alloys 

      Saito, Takeshi; Marioara, Calin Daniel; Røyset, Jostein; Holmestad, Randi (Journal article, 2014)
      The effect of cooling rate after solution heat treatment and its combination with 1% pre-deformation on precipitation hardening in two Al-Mg-Si alloys is investigated by transmission electron microscopy (TEM), and related ...

    • Effect of pre-deformation on age-hardening behaviors in an Al-Mg-Cu alloy 

      Chen, Xuanliang; Daehan, Kim; O, Minho; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Lervik, Adrian; Holmestad, Randi; Kobayashi, Equo (Peer reviewed; Journal article, 2021)
      The effects of 3%–50% pre-deformation following solution heat treatment on the age hardening of an Al-3Mg-1Cu alloy have been investigated by Vickers microhardness measurement, tensile tests, differential scanning calorimetry, ...

    • Effect of Pre-Deformation on Precipitation in Al–Zn–Mg–Cu Alloy 

      Rhee, Yujin; Thronsen, Elisabeth; Ryggetangen, Oskar; Marioara, Calin Daniel; Holmestad, Randi; Kobayashi, Equo (Journal article; Peer reviewed, 2024)
      In this work, strengthening effects and evolution of precipitates in a pre-deformed Al–Zn–Mg–Cu alloy during ageing were investigated using Vickers hardness measurements, tensile tests, and high angle annular dark field ...

    • Effect of room temperature storage time on precipitation in Al-Mg-Si(-Cu) alloys with different Mg/Si ratios 

      Wenner, Sigurd; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Holmestad, Randi (Journal article; Peer reviewed, 2012)
      The effect of natural ageing time before artificial ageing has been investigated in four Al – Mg – Si(– Cu) alloys, with 0.4 % Mg + 0.8 % Si and 0.8 % Mg + 0.4 % Si, both with and without 0.14 at.% Cu. The precipitate ...

    • The Effect of Small Additions of Fe and Heavy Deformation on the Precipitation in an Al–1.1Mg–0.5Cu–0.3Si At. Pct Alloy 

      Thronsen, Elisabeth; Mørkeseth, Hanne; Marioara, Calin Daniel; Minakuchi, Kazuhiro; Katsumi, Tetsuya; Marthinsen, Knut; Matsuda, Kenji; Holmestad, Randi (Journal article; Peer reviewed, 2022)
      The effect of 0.03 and 0.08 at. pct Fe additions on the formation of secondary phases in an Al–1.1Mg–0.5Cu–0.3Si at. pct alloy was investigated. Following solution heat treatment and natural aging, the alloys were analyzed ...

    • Effects of Germanium, Copper, and Silver Substitutions on Hardness and Microstructure in Lean Al-Mg-Si Alloys 

      Mørtsell, Eva Anne; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Røyset, Jostein; Reiso, Oddvin; Holmestad, Randi (Journal article; Peer reviewed, 2015)
      It is shown that strength loss in a 6060 Al-Mg-Si alloy caused by reduction in solute can be compensated by adding back smaller quantities of Ag, Ge, and Cu. Nine alloys were investigated. Ge was found to be the most ...