Browsing by Author "Li, Yanjun"
Now showing items 1-20 of 57
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Achieving dispersed fine soft Bi particles and grain refinement in a hypermonotectic Al-Bi alloy by severe plastic deformation and annealing
Zha, Min; Yu, Zhiyuan; Qian, Feng; Wang, Huiyuan; Li, Yanjun; Mathiesen, Ragnvald; Roven, Hans Jørgen (Journal article; Peer reviewed, 2018)The present work revealed that equal-channel angular pressing (ECAP) deformation combined with appropriate annealing could represent as an efficient route to modify immiscible as-cast microstructure of a monotectic Al–8Bi ... -
Al-5Cu alloy processed by equal-channel angular pressing
Jia, Hailong; Marthinsen, Knut; Li, Yanjun (Journal article; Peer reviewed, 2017)An ECAP (equal channel angular pressing) processed UFG Al-5Cu alloy was characterized by electron backscatter diffraction (EBSD). It is revealed that a bimodal grain structure, i.e. ultrafine grains accompanied by micron-sized ... -
A TEM Study of Weakly Overaged Precipitates in AA 6082
Sulen, Olav (Master thesis, 2016)New models for modeling the material properties for aluminium alloys that can take into consideration the geometry of the needle shaped precipitates, that can be found in 6xxx alloys are being developed. The background for ... -
A Thermodynamic Study on the Effect of Solute on the Nucleation Driving Force, Solid?Liquid Interfacial Energy, and Grain Refinement of Al Alloys
Xu, Yijiang; Zhao, Dongdong; Li, Yanjun (Journal article, 2018)Chemical composition is known to have significant effects on the grain refinement behavior of inoculated Al alloys during solidification. In this study, the influences of solute contents on the thermodynamic nucleation ... -
Carbon segregation at Σ3 {112} grain boundaries in silicon
Zhao, Dongdong; Li, Yanjun (Journal article; Peer reviewed, 2018)First-principles calculations were carried out to systematically investigate the carbon segregation along Σ3 {1 1 2} grain boundaries (GBs) in silicon. The energetically favorable segregation sites and corresponding ... -
Characterization of Iron Bearing Particles in Relation to Fir-Tree Structure in Al-Mg Alloys
Solli, Idun (Master thesis, 2018)Fir-tree structure is a well-known problem related to DC cast AA1xxx and AA5xxx alloys. During DC casting different iron bearing particles, e.g. AlmFe, Al3Fe and Al6Fe, are formed. A change of the dominating iron bearing ... -
Characterization the softening behavior of cold rolled AlMnFeSi-alloys during conditions of concurrent precipitation
Wang, Ning; Li, Yanjun; Marthinsen, Knut (Journal article, 2013)In the present work an Al-Mn-(Fe-Si) model alloy has been subjected to different homogenization treatments, to achieve materials with different microchemistry states in terms of constituents, levels of Mn in solid solution ... -
Combined effect of Mg and vacancy on the generalized planar fault energy of Al
Zhao, Dongdong; Løvvik, Ole Martin; Marthinsen, Knut; Li, Yanjun (Journal article; Peer reviewed, 2017)By first-principles calculations, a systematic study has been undertaken to investigate the combined effect of vacancies and Mg impurities on the generalized planar fault energy (GPFE) of pure Al. It was predicted that ... -
Deformation of an Al-7Mg alloy with extensive structural micro-segregations during dynamic plastic deformation
Jin, Shenbao; Tao, Nairong; Marthinsen, Knut; Li, Yanjun (Journal article; Peer reviewed, 2015)The microstructure evolution and deformation behavior of an as-cast Al–7Mg alloy with severe Mg segregation zones distributed on grain boundaries and in interdendrite regions subjected to dynamic plastic deformation (DPD) ... -
Effect of soft Bi particles on grain refinement during severe plastic deformation
Jia, Hailong; Marthinsen, Knut; Li, Yanjun (Journal article; Peer reviewed, 2017)Two aluminum alloys, Al–8Zn and Al–6Bi–8Zn were subjected to equal channel angular pressing (ECAP) up to 5 passes at room temperature. The microstructural evolution and the grain refinement behavior of these alloys were ... -
Effect of Surface Treatment and Preheating Temperature on Compound Casting of Aluminium Alloy A356 onto 6060 Inserts
Grasmo, Siren (Master thesis, 2019)For bilindustrien er det viktig å studere ulike metoder for å redusere kjøretøyvekt, da dette reduserer bensinforbruk, noe som vil ha både økonomiske og miljømessige fordeler. Hybridstøpning er å støpe et flytende materiale ... -
Effects of Surface Treatment on Hypoeutectoid Steels and Commercially Pure Copper in a Compound Casting Process with Aluminum A356 Alloy
Bakke, Aina Opsal (Master thesis, 2017)Evidence of climate change has caused industries worldwide to start measures towards reducing greenhouse gas emission. The automotive industry is a large contributor to emission and has therefore demanded production of ... -
Engineering grain boundary structures of aluminium alloys and titanium by high strain/ strain rate deformation
Jia, Hailong (Doctoral theses at NTNU;2018:139, Doctoral thesis, 2018)A comprehensive study was carried out to clarify the effects of severe plastic deformation (SPD) and high strain rate deformation on various aluminium alloys and commercial purity titanium. Equal channel angular pressing ... -
Enhanced dispersoid precipitation and dispersion strengthening in an Al alloy by microalloying with Cd
Qian, Feng; Jin, Shenbao; Sha, Gang; Li, Yanjun (Journal article; Peer reviewed, 2018)The dispersion hardening effect of Mn(Fe)-containing dispersoids in aluminium alloys has long been ignored since it is difficult to achieve a high number density of fine dispersoids with conventional alloying compositions. ... -
Evolution in microstructure and properties during non-isothermal annealing of a cold-rolled Al-Mn-Fe-Si alloy with different microchemistry states
Huang, Ke; Engler, Olaf; Li, Yanjun; Marthinsen, Knut (Journal article, 2015)The softening behaviour during non-isothermal annealing of a cold-rolled Al–Mn–Fe–Si model alloy was studied as a function of the state of microchemistry, in terms of the solute level of Mn, size and spatial distribution ... -
Experimental and numerical modelling study on the nucleation and grain growth of inoculated aluminium alloys
Xu, Yijiang (Doctoral theses at NTNU;2017:343, Doctoral thesis, 2017)With the aim to achieve an in-depth understanding on the heterogeneous nucleation and grain growth behavior during solidification of inoculated aluminum alloys, an integrated study by in-situ X-radiography, numerical ... -
Faceted interfacial structure of {1011} twins in Ti formed during equal channel angular pressing
Li, Yanjun; Chen, Yongjun; Walmsley, John C.; Mathiesen, Ragnvald; Dumoulin, S; Roven, Hans Jørgen (Journal article; Peer reviewed, 2010)The boundary structure of {1011} deformation twins formed in commercial pure titanium (CP-Ti) during the initial pass ECAP processing has been studied by TEM and HRTEM. A new twining mode with twinning dislocation of b3/3, ... -
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 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 ...