Browsing NTNU Open by Author "Saito, Takeshi"
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Aberration-corrected HAADF-STEM investigations of precipitate structures in Al-Mg-Si alloys with low Cu additions
Saito, Takeshi; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Lefebvre, Williams; Holmestad, Randi (Journal article, 2014)Precipitates in a lean Al–Mg–Si alloy with low Cu addition (~0.10 wt.%) were investigated by aberration-corrected high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). Most precipitates were ... -
Atomic structures of precipitates in Al–Mg–Si alloys with small additions of other elements
Saito, Takeshi; Mørtsell, Eva Anne; Wenner, Sigurd; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Friis, Jesper; Matsuda, Kenji; Holmestad, Randi (Journal article; Peer reviewed, 2018)In Al–Mg–Si alloys, additions of only a few weight percent of Mg and Si enable formation of hardening precipitates during heat treatment. The precipitation is complex and is influenced by chemical compositions and ... -
Chemical Modification of Al-Mg2Si Eutectic With Additions of Calcium and Strontium
Linga, Håkon (Master thesis, 2020)Eutektiske og legeringer nær eutektisk komposisjon er vanlege å bruke til støping på grunn av ypperlige støpeegenskaper, og ein slik legering er Al-5Mg-2Si som danner ein stor andel av den eutektiske fasen Al-Mg2Si. Sjølv ... -
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 ... -
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 ... -
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 ... -
HAADF-STEM and DFT investigations of the Zn-containing β'' phase in Al-Mg-Si alloys
Saito, Takeshi; Ehlers, Flemming J H; Lefebvre, Williams; Hernandez-Maldonado, D; Bjørge, Ruben; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Holmestad, Randi (Journal article, 2014)The Zn-containing β″ phase in Al–Mg–Si alloys was investigated by aberration corrected high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), combined with density functional theory (DFT) ... -
How Slight Solidification Rate Variations within Cast Plate Affect Mechanical Response: A Study on As-Cast A356 Alloy with Cu Addition
Di Giovanni, Maria Teresa; Cerri, Emanuela; Saito, Takeshi; Akhtar, Shahid; Åsholt, Petter; Li, Yanjun; Di Sabatino Lundberg, Marisa (Journal article; Peer reviewed, 2018)The present work investigates a narrow range of secondary dendrite arm spacing (SDAS), in an as-cast A356 alloy with and without copper (Cu) additions. Cu was added to the base A356 alloy melt to reach the target concentration ... -
Influence of low Cu addition on quench sensitivity in Al-Mg-Si alloys
Saito, Takeshi; Marioara, Calin Daniel; Røyset, Jostein; Holmestad, Randi (Journal article, 2014)Quench sensitivity in two Al-Mg-Si alloys, one Cu-free and the other with low Cu additions (~0.1 wt%), both having the same amounts of other solutes, has been investigated using transmission electron microscopy (TEM) and ... -
Karakterisering av mikrostruktur og mekaniske egenskaper til selektiv lasersmeltet AlSi10Mg og AlSi7MgCuHf, direkte på en AlSi7MgCu støpelegering
Opøien, Elin; Skogen Brataas, Martine Sol (Master thesis, 2019)Selektiv lasersmelting (SLS) er en av flere metoder under additiv tilvirkning. Produktet bygges ved at en laser smelter pulverpartikler sammen lag for lag. Til forskjell fra de konvensjonelle metodene som støping, ekstrudering ... -
Karakterisering av mikrostruktur og mekaniske egenskaper til selektiv lasersmeltet AlSi10Mg og AlSi7MgCuHf, direkte på en AlSi7MgCu støpelegering
Skogen Brataas, Martine Sol; Opøien, Elin (Master thesis, 2019)Selektiv lasersmelting (SLS) er en av flere metoder under additiv tilvirkning. Produktet bygges ved at en laser smelter pulverpartikler sammen lag for lag. Til forskjell fra de konvensjonelle metodene som støping, ekstrudering ... -
Structural investigation of precipitates with Cu and Zn atomic columns in Al-Mg-Si alloys by aberration-corrected HAADF-STEM
Saito, Takeshi; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Lefebvre, Williams; Holmestad, Randi (Journal article; Peer reviewed, 2014)Precipitates in Al-Mg-Si alloys with Cu addition (~0.1 wt%) and Zn addition (~1 wt%) were investigated by aberration corrected high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). Most ... -
The Effect of Trace Elements on Precipitation in Al-Mg-Si alloys - A Transmission Electron Microscopy Study
Saito, Takeshi (Doktoravhandlinger ved NTNU, 1503-8181; 2014:171, Doctoral thesis, 2014)Atomic scale studies of aluminum alloys The thesis focuses on structural analysis of particles (precipitates) in the important aluminum alloys – Al-Mg-Si alloys, studied by transmission electron microscopy (TEM) including ... -
The Effect of Zn on precipitation in Al-Mg-Si alloys
Saito, Takeshi; Wenner, Sigurd; Osmundsen, Elisa; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Røyset, Jostein; Lefebvre, Williams; Holmestad, Randi (Journal article, 2014)Effects of addition of Zn (up to 1 wt%) on microstructure, precipitate structure and intergranular corrosion (IGC) in an Al–Mg–Si alloys were investigated. During ageing at 185 °C, the alloys showed modest increases in ... -
The Effects of Low Cu Additions and Predeformation on the Precipitation in a 6060 Al-Mg-Si Alloy
Saito, Takeshi; Muraishi, Shinji; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Jostein, Røyset; Holmestad, Randi (Journal article, 2013)Effects of low Cu additions (≤0.10 wt pct) and 10 pct predeformation before aging on precipitates’ microstructures and types in a 6060 Al-Mg-Si alloy have been investigated using transmission electron microscopy (TEM). It ... -
The effects of quench rate and pre-deformation on precipitation hardening in Al–Mg–Si alloys with different Cu amounts
Saito, Takeshi; Marioara, Calin Daniel; Røyset, Jostein; Marthinsen, Knut; Holmestad, Randi (Journal article, 2014)The effects of quench rate after solution heat treatment in combination with 1% pre-deformation on precipitation hardening in three Al–Mg–Si alloys have been investigated by transmission electron microscopy and hardness ...