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Andersson, Nils-EricORCID iD iconorcid.org/0000-0001-6445-6005
Publications (10 of 22) Show all publications
Eslami, M., Speranza, G., Fedel, M., Andersson, N.-E., Deflorian, F., Omanovic, S. & Zanella, C. (2019). Electropolymerization and possible corrosion protection effect of polypyrrole coatings on AA1050 (UNS A91050) in NaCl solutions. Corrosion, 75(7), 745-755
Open this publication in new window or tab >>Electropolymerization and possible corrosion protection effect of polypyrrole coatings on AA1050 (UNS A91050) in NaCl solutions
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2019 (English)In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 75, no 7, p. 745-755Article in journal (Refereed) Published
Abstract [en]

Effect of solution chemistry on the electropolymerization and the electrochemical properties of polypyrrole coatings on aluminum is studied by means of electrochemical techniques, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy. It is shown that the protection effect of the coating in long-term exposures and when exposed to more concentrated NaCl solutions depends on the chemistry of electropolymerization electrolyte. The results show that nitrate anions passivate the aluminum substrate during the electropolymerization process. The resulting coating is less prone to blistering in a NaCl solution and probably due to its higher electrochemical activity presents a higher anodic protection effect. The galvanic interaction of polypyrrole coating with aluminum in a NaCl solution is directly observed using focused ion beam-assisted SEM.

Place, publisher, year, edition, pages
National Association of Corrosion Engineers International, 2019
Keywords
Aluminum, Conductive polymer, Corrosion protection, Galvanic interaction, Passivation, Polypyrrole, Aluminum coatings, Aluminum corrosion, Anodic protection, Electrolytes, Electropolymerization, Galvanic corrosion, Ion beams, Polypyrroles, Scanning electron microscopy, Sodium chloride, X ray photoelectron spectroscopy, Aluminum substrate, Electrochemical activities, Electrochemical techniques, Long term exposure, Polypyrrole coatings, Solution chemistry, Corrosion resistant coatings
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-45537 (URN)10.5006/3124 (DOI)000474438600005 ()2-s2.0-85069675948 (Scopus ID)HOA JTH 2019;JTHMaterialIS (Local ID)HOA JTH 2019;JTHMaterialIS (Archive number)HOA JTH 2019;JTHMaterialIS (OAI)
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-13Bibliographically approved
Dini, H., Andersson, N.-E. & Jarfors, A. E. .. (2018). Effect of process parameters on distortion and residual stress of high-pressure die-cast AZ91D components. International Journal of metalcasting, 12(3), 487-497
Open this publication in new window or tab >>Effect of process parameters on distortion and residual stress of high-pressure die-cast AZ91D components
2018 (English)In: International Journal of metalcasting, ISSN 1939-5981, E-ISSN 2163-3193, Vol. 12, no 3, p. 487-497Article in journal (Refereed) Published
Abstract [en]

This paper presents a study of distortion and residual stress within a high-pressure die-cast AZ91D component, cast under different processing conditions. The influence of process parameters, i.e., die temperature, cooling time, intensification pressure and first-phase injection speeds, was examined. Distortions were measured using the in-house standard analog quality control fixture. Residual stress depth profiles were measured using a prism hole-drilling method. It was found that the most important process parameter affecting the distortion was intensification pressure and the second most important was temperature difference between the two die halves (fixed and moving side). Tensile residual stresses were found very near the surface. Increasing the intensification pressure resulted in an increased level of tensile residual stresses.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
magnesium alloy; high-pressure die cast; distortion; residual stress
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-38146 (URN)10.1007/s40962-017-0186-z (DOI)000436927100010 ()2-s2.0-85049327484 (Scopus ID)HOA JTH 2018 (Local ID)HOA JTH 2018 (Archive number)HOA JTH 2018 (OAI)
Available from: 2017-12-12 Created: 2017-12-12 Last updated: 2019-02-14Bibliographically approved
Dini, H., Svoboda, A., Andersson, N.-E., Ghassemali, E., Lindgren, L.-E. & Jarfors, A. E. .. (2018). Optimization and validation of a dislocation density based constitutive model for as-cast Mg-9%Al-1%Zn. Materials Science & Engineering: A, 710, 17-26
Open this publication in new window or tab >>Optimization and validation of a dislocation density based constitutive model for as-cast Mg-9%Al-1%Zn
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2018 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 710, p. 17-26Article in journal (Refereed) Published
Abstract [en]

A dislocation density-based constitutive model, including effects of microstructure scale and temperature, was calibrated to predict flow stress of an as-cast AZ91D (Mg-9%Al-1%Zn) alloy. Tensile stress-strain data, for strain rates from 10-4 up to 10-1 s-1 and temperatures from room temperature up to 190 °C were used for model calibration. The used model accounts for the interaction of various microstructure features with dislocations and thereby on the plastic properties. It was shown that the Secondary Dendrite Arm Spacing (SDAS) size was appropriate as an initial characteristic microstructural scale input to the model. However, as strain increased the influence of subcells size and total dislocation density dominated the flow stress. The calibrated temperature-dependent parameters were validated through a correlation between microstructure and the physics of the deforming alloy. The model was validated by comparison with dislocation density obtained by using Electron Backscattered Diffraction (EBSD) technique.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Casting methods, Characterization, Magnesium alloy, Optimization, Physically-based model, Plasticity, Aluminum, Aluminum alloys, Constitutive models, Magnesium castings, Microstructure, Plastic flow, Strain rate, Ternary alloys, Zinc, Zinc alloys, Zirconium alloys, Casting method, Dislocation densities, Electron back-scattered diffraction, Model calibration, Physically based modeling, Secondary dendrite arm spacing, Temperature dependent, Tensile stress strain, Magnesium alloys
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-38144 (URN)10.1016/j.msea.2017.10.081 (DOI)000429888200003 ()2-s2.0-85032297009 (Scopus ID)
Available from: 2017-12-12 Created: 2017-12-12 Last updated: 2018-09-21Bibliographically approved
Zamani, M., Dini, H., Svoboda, A., Lindgren, L.-E., Seifeddine, S., Andersson, N.-E. & Jarfors, A. (2017). A dislocation density based constitutive model for as-cast Al-Si alloys: Effect of temperature and microstructure. International Journal of Mechanical Sciences, 121, 164-170
Open this publication in new window or tab >>A dislocation density based constitutive model for as-cast Al-Si alloys: Effect of temperature and microstructure
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2017 (English)In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 121, p. 164-170Article in journal (Refereed) Published
Abstract [en]

The flow stress of an as-cast Al-Si based alloy was modeled using a dislocation density based model. The developed dislocation density-based constitutive model describes the flow curve of the alloy with various microstructures at quite wide temperature range. Experimental data in the form of stress-strain curves for different strain rates ranging from 10−4 to 10−1 s−1 and temperatures ranging from ambient temperature up to 400 °C were used for model calibration. In order to model precisely the hardening and recovery process at elevated temperature, the interaction between vacancies and dissolved Si was included. The calibrated temperature dependent parameters for different microstructure were correlated to the metallurgical event of the material and validated. For the first time, a dislocation density based model was successfully developed for Al-Si cast alloys. The findings of this work expanded the knowledge on short strain tensile deformation behaviour of these type of alloys at different temperature, which is a critical element for conducting a reliable microstructural FE-simulation.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Aluminium cast alloy; Dislocation density; Eutectic phase; Si precipitation; Si solute; Vacancy concentration
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-27375 (URN)10.1016/j.ijmecsci.2017.01.003 (DOI)000395216300015 ()2-s2.0-85008703756 (Scopus ID)
Note

Finns som manuskript med titeln A Dislocation Density Based Yield Stress Model for as-cast EN AC-46000 Alloy i licentiatuppsats. 

Available from: 2015-06-22 Created: 2015-06-22 Last updated: 2017-12-12Bibliographically approved
Zhu, B., Fedel, M., Andersson, N.-E., Leisner, P., Deflorian, F. & Zanella, C. (2017). Effect of Si content and morphology on corrosion resistance of anodized cast Al-Si alloys. Journal of the Electrochemical Society, 164(7), C435-C441
Open this publication in new window or tab >>Effect of Si content and morphology on corrosion resistance of anodized cast Al-Si alloys
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2017 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 7, p. C435-C441Article in journal (Refereed) Published
Abstract [en]

This paper investigates the influence of Si content and Si particle morphology on the corrosion protection of anodized oxide layers on Al-Si alloys. Two Al alloys with low Si concentrations (2.43 wt-% and 5.45 wt-%, respectively) were studied and compared with 6082-T6 via electrochemical impedance spectroscopy (EIS) in 3 wt-% NaCl solution prior to oxide layer sealing. Si particles were also modified by the addition of Sr to study the influence of Si particle morphology on the corrosion protection of the oxide layer. The EIS showed that the corrosion protection provided by the oxide layer on Al-Si alloys is significantly affected by the presence of Si particles. Si particles make the oxide layer locally thinner and more defective in the eutectic region, thereby increasing the ease of substrate corrosion attack. However, the addition of Sr can improve the corrosion protection of anodized Al-Si alloys significantly. Furthermore, it was proved that higher Si level influences negatively the anodized oxide corrosion protection due to the higher amount of cracks and defects, but Sr modification is efficient in preventing this negative effect.

Place, publisher, year, edition, pages
The Electrochemical Society, 2017
Keywords
cast Al-Si alloys, anodising, EIS, 3D tomography
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-35095 (URN)10.1149/2.1631707jes (DOI)000404397300077 ()2-s2.0-85020855659 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Note

Part of licentiate thesis in its submitted form.

Available from: 2017-02-17 Created: 2017-02-17 Last updated: 2019-05-09Bibliographically approved
Zhu, B., Fedel, M., Andersson, N.-E., Leisner, P., Deflorian, F. & Zanella, C. (2017). Influence of the Sr modification and post-treatment on corrosion resistance of oxide layer of cast Al-(low)Si alloys. In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017: . Paper presented at Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017; Prague; Czech Republic; 3 - 7 September 2017 (pp. 27-39). Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers
Open this publication in new window or tab >>Influence of the Sr modification and post-treatment on corrosion resistance of oxide layer of cast Al-(low)Si alloys
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2017 (English)In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers , 2017, p. 27-39Conference paper, Published paper (Refereed)
Abstract [en]

The current development of casting process makes it possible to cast low Si content aluminium alloys, which open the gate for the application of anodising on cast aluminium components. This paper aims to investigate the influence of Sr modification as well as the post-treatment on corrosion resistance of oxide layer of low Si content cast Al alloys. In the present study, designed Al-Si alloys with 5.45 wt-% Si were studied by performing electrochemical impedance spectroscopy (EIS) in 3 wt-% NaCl solution. The morphology of Si particle was determined by controlling the level of Sr. The microstructure features were evaluated by optical microscopy and scanning electron microscopy (SEM). Furthermore, focus ion beam-SEM (FIB-SEM) equipped with energy-dispersive X-ray spectroscopy (EDXS) was applied to exam the corrosion morphology and the anodised layer with Si rich eutectic phases. The EIS study revealed that the corrosion resistance of the oxide layer on cast Al alloys can be significantly influenced by the morphology of Si particle and the post-treatment. It was found that the change of Si particle morphology from flake-like to fibrous by Sr addition can substantially improve the corrosion resistance of the oxide layer in the unsealed condition due to the formation of the more compacted oxide layer with less defects. Normally, the application of a sealing step such as the hydrothermal sealing can improve the corrosion protection of the oxide layer. However, in the current study, it was found the hydrothermal sealing step leads to a significant reduce of the corrosion protection due to the generation of cracks into the oxide layer, and the hydrothermal sealing step can counteract the improvement of the corrosion protection by Sr addition.

Place, publisher, year, edition, pages
Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers, 2017
Keywords
Anodising, Cast Al-Si alloys, Corrosion resistance, EIS, FIB-SEM, Aluminum alloys, Corrosion protection, Corrosion resistant alloys, Electrochemical corrosion, Electrochemical impedance spectroscopy, Energy dispersive spectroscopy, Ion beams, Morphology, Scanning electron microscopy, Silicon alloys, Sodium chloride, Strontium, Casting process, Corrosion morphology, Energy dispersive x-ray spectroscopy, FIB SEM, Hydrothermal sealing, Sr modification, Aluminum corrosion
National Category
Corrosion Engineering
Identifiers
urn:nbn:se:hj:diva-41534 (URN)2-s2.0-85052280685 (Scopus ID)
Conference
Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017; Prague; Czech Republic; 3 - 7 September 2017
Available from: 2018-09-24 Created: 2018-09-24 Last updated: 2019-05-09Bibliographically approved
Dini, H., Svoboda, A., Andersson, N.-E., Ghassemali, E., Lindgren, L. & Jarfors, A. E. .. (2017). Modeling the Deformation Behavior of As-Cast AZ1D Including the Effect of The Cast Microstructure. In: Proceedings of PLASTICITY ’17: The Twenty Third International Conference on Plasticity, Damage, and Fracture: . Paper presented at The Twenty Third International Conference on Plasticity, Damage, and Fracture, January 3-9, 2017, Puerto Vallarta, Mexico (pp. 37-39).
Open this publication in new window or tab >>Modeling the Deformation Behavior of As-Cast AZ1D Including the Effect of The Cast Microstructure
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2017 (English)In: Proceedings of PLASTICITY ’17: The Twenty Third International Conference on Plasticity, Damage, and Fracture, 2017, p. 37-39Conference paper, Published paper (Refereed)
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-38142 (URN)
Conference
The Twenty Third International Conference on Plasticity, Damage, and Fracture, January 3-9, 2017, Puerto Vallarta, Mexico
Available from: 2017-12-12 Created: 2017-12-12 Last updated: 2018-09-21Bibliographically approved
Eslami, M., Fedel, M., Speranza, G., Deflorian, F., Andersson, N.-E. & Zanella, C. (2017). Study of selective deposition mechanism of cerium-based conversion coating on Rheo-HPDC aluminium-silicon alloys. Electrochimica Acta, 255, 449-462
Open this publication in new window or tab >>Study of selective deposition mechanism of cerium-based conversion coating on Rheo-HPDC aluminium-silicon alloys
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2017 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 255, p. 449-462Article in journal (Refereed) Published
Abstract [en]

Cerium-based conversion coatings were deposited on Rheo-High Pressure Die Cast (HPDC) Al-Si alloys by immersion in cerium nitrate aqueous solutions. Rheocast Al-Si alloys have a heterogeneous microstructure and present a challenge for the conversion treatment. Different parameters were studied to optimize the conversion coating, and NaCl or H2O2 were also added to the solution to modify or accelerate the deposition process. The mechanism of the coating formation was studied by means of focused ion beam milling (FIB) assisted SEM. The results show that applying cerium-based conversion coating to Al-Si alloys, is possible and a preferential deposition is obtained due to the presence of iron-rich intermetallic particles inside the eutectic region. The formation mechanism of selectively deposited cerium-based conversion coating includes dissolution of aluminium matrix, selective dissolution of aluminium from the noble intermetallic particles, oxidation of iron from the intermetallic particles, and the deposition of cerium hydroxide/oxide layer. The results reveal that the improvement in corrosion resistance in the presence of selectively deposited cerium-based conversion coating is more significant compared to the homogenous coating deposited from the conversion solution containing H2O2. 

Place, publisher, year, edition, pages
Pergamon Press, 2017
Keywords
ELECTROCHEMICAL MICRO-CELL; DIE-CASTING PROCESS; 2024-T3 AL-ALLOY; CORROSION PROTECTION; PITTING CORROSION; A3XX.X/SICP COMPOSITES; SUBSURFACE CREVICES; NACL SOLUTION; SI ALLOYS; 7075-T6
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-38203 (URN)10.1016/j.electacta.2017.09.182 (DOI)000413445000048 ()2-s2.0-85030858525 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Available from: 2017-12-15 Created: 2017-12-15 Last updated: 2019-01-18Bibliographically approved
Dini, H., Andersson, N.-E. & Jarfors, A. E. .. (2016). Effect of Mg17Al12 Fraction on Mechanical Properties of Mg-9%Al-1%Zn Cast Alloy. Metals, 6(10), Article ID 251.
Open this publication in new window or tab >>Effect of Mg17Al12 Fraction on Mechanical Properties of Mg-9%Al-1%Zn Cast Alloy
2016 (English)In: Metals, ISSN 2075-4701, Vol. 6, no 10, article id 251Article in journal (Refereed) Published
Abstract [en]

In the current study it was observed that the offset yield point of Mg-9%Al-1%Zn alloy was strongly influenced by the connectivity of Mg17Al12. It was suggested that an increase in the fraction of Mg17Al12 from 8% to 11% could lead to the formation of a Mg17Al12 network which resulted in a higher offset yield point. In addition, it was observed that elongation to failure of the Mg-9%Al-1%Zn alloy strongly depended on the fraction of Mg17Al12. Moreover, the apparent toughness showed a strong inverse relation to the secondary dendrite arm spacing. This approach might be extended to forecast the behavior in other magnesium alloys forming a network of the Mg-Al phase.

Keywords
casting, microstructure, tension test, magnesium alloys, mechanical properties
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-34778 (URN)10.3390/met6100251 (DOI)000388888100024 ()2-s2.0-84995680440 (Scopus ID)
Available from: 2017-01-18 Created: 2017-01-18 Last updated: 2017-12-12Bibliographically approved
Dini, H., Andersson, N.-E., Ghassemali, E. & Jarfors, A. E. .. (2015). Microstructural Scale Effects on Thermal Expansion Behaviour of Cast AZ91D. In: Magnesium Technology 2015 - TMS 2015 144th Annual Meeting and Exhibition, Orlando, March 15-19, 2015: . Paper presented at Magnesium Technology 2015 - TMS 2015 (pp. 361-365). Hoboken: John Wiley & Sons
Open this publication in new window or tab >>Microstructural Scale Effects on Thermal Expansion Behaviour of Cast AZ91D
2015 (English)In: Magnesium Technology 2015 - TMS 2015 144th Annual Meeting and Exhibition, Orlando, March 15-19, 2015, Hoboken: John Wiley & Sons, 2015, p. 361-365Conference paper, Published paper (Refereed)
Abstract [en]

The effect of microstructure on thermal expansion of AZ91D cast alloy was studied. Samples with equiaxed grains and a controlled secondary dendrite arm spacing (SDAS) were fabricated using gradient solidification. SDAS was chosen to represent the range ofmicrostructural scale found in sand castings down to that of high pressure die casting. Optical microscopy and electron backscatter diffraction (EBSD) were used for microstructural characterization. The relation between thermal expansion and microstructuralscale of existing phases precipitated, in particular grain size, SDAS and fraction of Mg17Al12 was analyzed.

Place, publisher, year, edition, pages
Hoboken: John Wiley & Sons, 2015
Keywords
AZ91D, Magnesium, Mg17Al12, Microstructure, Thermal expansion
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-28486 (URN)10.1002/9781119093428.ch67 (DOI)2-s2.0-84942124208 (Scopus ID)978-111908243-9 (ISBN)
Conference
Magnesium Technology 2015 - TMS 2015
Available from: 2015-12-07 Created: 2015-12-07 Last updated: 2017-12-12Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-6445-6005

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