Blar i NTNU Open på forfatter "Li, Yanjun"
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Formation of incoherent deformation twin boundaries in a coarse-grained Al-7Mg alloy
Jin, Shenbao; Zhang, Kai; Bjørge, Ruben; Tao, NR; Marthinsen, Knut; Lu, K; Li, Yanjun (Journal article; Peer reviewed, 2015)Deformation twinning has rarely been observed in coarse grained Al and its alloys except under some extreme conditions such as ultrahigh deformation strain or strain rates. Here, we report that a significant amount of Σ3 ... -
Formation of Primary Silicon and its Influence on the Eutectic Solidification in Unmodified Hypoeutectic Al-Si Alloys - Investigation of Orientation Relationships by EBSD
Hendawi, Rania (Master thesis, 2018)Nucleation and growth of the primary and eutectic silicon in unmodified hypoeutectic Al-Si alloy have been investigated for via optical microscopy, EBSD and SEM . The influence of the cooling rate and phosphorus concentration ... -
Formation of {11-21} twin boundaries in titanium by kinking mechanism through accumulative dislocation slip
Jin, Shenbao; Marthinsen, Knut; Li, Yanjun (Journal article; Peer reviewed, 2016)The twinning behavior and kinking behavior of a commercial purity Ti subjected to room temperature dynamic plastic deformation (DPD) has been studied. Three types of deformation twins, {1012}, {1122} and {1121}, have been ... -
Formation of Σ3{110} incoherent twin boundaries through geometrically necessary boundaries in an Al-8Zn alloy subjected to one pass of equal channel angular pressing
Jia, Hailong; Jin, Shenbao; Li, Yanjun (Journal article, 2018)For coarse grained (CG) alloys with high stacking fault energies (SFEs), like aluminum, deformation twins can rarely form. Here, we report that Σ3{110} incoherent twin boundaries (ITBs) could be generated in a CG Al-8Zn ... -
Freezing solute atoms in nanograined aluminum alloys via high-density vacancies
Wu, Shenghua; Søreide, Hanne-Sofie; Li, Chunan; Liu, gang; Li, Yanjun; Roven, Hans Jørgen; Sun, Jun (Peer reviewed; Journal article, 2022)Low-temperature decomposition of supersaturated solid solution into unfavorable intergranular precipitates is a long-standing bottleneck limiting the practical applications of nanograined aluminum alloys that are prepared ... -
Grain boundary segregation in Pd-Cu-Ag alloys for high permeability hydrogen separation membranes
Løvvik, Ole Martin; Zhao, Dongdong; Li, Yanjun; Bredesen, Rune; Peters, Thijs (Journal article; Peer reviewed, 2018)Dense metal membranes that are based on palladium (Pd) are promising for hydrogen separation and production due to their high selectivity and permeability. Optimization of alloy composition has normally focused on bulk ... -
Heterogeneous nucleation and grain growth of inoculated aluminium alloys: An integrated study by in-situ X-radiography and numerical modelling
Xu, Yijiang; Casari, Daniele; Du, Qiang; Mathiesen, Ragnvald; Arnberg, Lars; Li, Yanjun (Journal article; Peer reviewed, 2017)A comprehensive study on the heterogeneous nucleation and grain growth of Al-10 wt.%Cu alloys inoculated with Al-5Ti-1B was carried out. To further reveal the solute segregation stifling mechanism, in-situ near-isothermal ... -
Hierarchical structure in Al-Cu alloys to promote strength/ductility synergy
Wu, Shenghua; Li, Yanjun; Roven, Hans Jørgen; Liu, gang; Sun, Jun (Peer reviewed; Journal article, 2021)Experimental evidence demonstrated that equal channel angular pressing (ECAP) at cryogenic temperature, in comparison with ECAP at room temperature, led to promoted strength-ductility synergy in an Al-2.5wt.%Cu alloy. The ... -
High strength and ductile high solid solution Al-Mg alloy processed by a novel hard-plate rolling route
Zha, Min; Meng, Xiaotao; Zhang, Hongmin; zhang, Xuanhe; Jia, Hailong; Li, Yanjun; Zhang, Junyu; Wang, Huiyuan; Jiang, Qichuan (Journal article, 2017)Achieving bimodal grain structure via cold rolling remains a challenge for Al–Mg alloys. In the present work, a high tensile strength (∼525 MPa) and ductile (∼14%) Al–9Mg alloy was fabricated by a novel hard-plate rolling ... -
High-energy X-ray Transmission Microscopy based on Compound Refractive Lenses
Falch, Ken Vidar (Doctoral theses at NTNU;2017:124, Doctoral thesis, 2017)Summary of thesis: In the results of the work presented in this thesis it has been shown theoretically and demonstrated experimentally that lateral chromatic aberration in hard x-ray transmission microscopy can be ... -
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 ... -
Improving ageing kinetics and precipitation hardening in an Al-Mg-Si alloy by minor Cd addition
Qian, Feng; Mørtsell, Eva Anne; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Li, Yanjun (Journal article; Peer reviewed, 2018)This study reports significant improvements in both the age hardening kinetics and peak hardness of an Al-Mg-Si alloy by microalloying with 0.06 at% Cd. A detailed high-angle annular dark-field scanning transmission electron ... -
Impurity effect of Mg on the generalized planar fault energy of Al
Zhao, Dongdong; Løvvik, Ole Martin; Marthinsen, Knut; Li, Yanjun (Journal article; Peer reviewed, 2016)Generalized planar fault energy (GPFE) curves are widely used to evaluate the deformation behavior of metals and alloys. In the present work, a systematic analysis of the microscopic plastic deformation mechanism of ... -
Impurity segregation at defects in Al and Si -A theoretical DFT based study
Zhao, Dongdong (Doctoral theses at NTNU;2017:273, Doctoral thesis, 2017)Alien impurity elements favor to stay at the defects, e.g. stacking fault, grain boundary (GB) in host materials and thus influence many material properties. On basis of atomistic simulations, the present thesis puts a ... -
In-situ X-radiographic study of nucleation and growth behaviour of primary silicon particles during solidification of a hypereutectic Al-Si alloy
Xu, Yijiang; Deng, Yun; Casari, Daniele; Mathiesen, Ragnvald; Li, Yanjun (Peer reviewed; Journal article, 2020)Real-time observation of structure evolution in a hypereutectic Al-Si(-Cu) alloy under near-isothermal melt solidification condition was conducted by using in-situ micro-focus X-radiography. The nucleation, growth rate and ... -
Influence of dispersoids on microstructure evolution and work hardening of aluminium alloys during tension and cold rolling
Zhao, Qinglong; Holmedal, Bjørn; Li, Yanjun (Journal article; Peer reviewed, 2013)The influence of dispersoids on work hardening of aluminium during tension and cold rolling has been studied by comparing Al–Mn alloys containing similar amounts of solutes but various dispersoid densities. The microstructure ... -
Influence of grain refiners on the wettability of Al2O3 substrate by aluminum melt
Yang, Jiawei; Bao, Sarina; Akhtar, Shahid; Shen, Ping; Li, Yanjun (Peer reviewed; Journal article, 2020)It is well known that grain refiner additions in aluminum melts significantly reduce the filtration efficiency of ceramic foam filters (CFF). However, the mechanism remains unclear. In this work, the influence of grain ... -
Influence of impurity elements on the precipitation behaviour of dispersoids and their hardening effects in aluminium alloys
Onsøien, Marit (Master thesis, 2017)Three different types of alloys have been investigated with respect to hardness, conductivity, strength and microstructural analysis using SEM and TEM. -
Influence of natural aging and ramping before artificial aging on the microstructure of two different 6xxx alloys
Hell, Christoph Martin; Søreide, Hanne-Sofie Marie Scisly; Bjørge, Ruben; Marioara, Calin Daniel; Li, Yanjun; Holmestad, Randi (Peer reviewed; Journal article, 2022)In this study the effect of a ramp up to artificial aging (AA) temperature in combination with natural aging (NA) was analyzed for two different industrial aluminium alloys. The alloys differ in their Mg/Si ratio as well ... -
The Influences of Grain Refiner, Inclusion Level, and Filter Grade on the Filtration Performance of Aluminum Melt
Yang, Jiawei; Bao, Sarina; Akhtar, Shahid; Tundal, Ulf; Tjøtta, Stig; Li, Yanjun (Peer reviewed; Journal article, 2021)The addition of grain refiner particles in the aluminum melt is known to reduce the filtration efficiency of ceramic foam filter (CFF). In the present work, a systematic study on the influence of the addition level of ...