scholarly journals Corrosion Behavior of Cold-Formed AA5754 Alloy Sheets

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 394
Author(s):  
Anna Dobkowska ◽  
Agata Sotniczuk ◽  
Piotr Bazarnik ◽  
Jarosław Mizera ◽  
Halina Garbacz
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Open Circuit ◽  
Alloy Sheet ◽  
Original Form ◽  
Coarse Particles ◽  
Electrochemical Polarization ◽  
Transmission Electron ◽  
Complex Process ◽  
Corrosion Mechanisms

In this work, the influence of bending an AA5457 alloy sheet and the resulting microstructural changes on its corrosion behavior was investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to perform detailed microstructural analyses of the alloy in its original form and after bending. After immersion in naturally-aged NaCl under open-circuit conditions (0.5 M, adjusted to 3 by HCl), post-corrosion observations were made, and electrochemical polarization measurements were performed to investigate the corrosion mechanisms occurring on both surfaces. The results showed that the corrosion of AA5457 is a complex process that mainly involves trenching around coarse Si-rich particles, crystallographically-grown large pits, and the formation of multiple tiny pits around Si-rich nanoparticles. The experimental data showed that bending AA5457 changed the shape and distribution of Si-rich coarse particles, cumulated a higher dislocation density in the material, especially around Si-rich nanoparticles, and all of these factors caused that corrosion behavior of the AA5754 in the bending area was lowered.

Effect of Microstructure Evolution on Corrosion Behavior of Friction Stir Welded Joint for 2195-T8 Alloy

CORROSION ◽  
10.5006/3567 ◽  
2020 ◽  
Vol 76 (12) ◽  
Author(s):  
B.Y. Hu ◽  
H. Zhang ◽  
L.Y. Liu ◽  
D.B. Liu ◽  
A.H. Feng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Open Circuit Potential ◽  
Galvanic Corrosion ◽  
Open Circuit ◽  
Nugget Zone ◽  
Friction Stir ◽  
Free Zone ◽  
Transmission Electron

Corrosion behavior of friction stir welded 2195-T8 Al-Cu-Li alloy has been studied. Immersion and electrochemical open-circuit potential (OCP) test were applied. The microstructure and precipitates evolution in different zones were investigated by scanning electron microscopy, stereoscope, and transmission electron microscopy. The corrosion tests showed that the sequence of corrosion resistance of each area of the joint is: welding nugget zone (WNZ) > base metal > heat affected zone (HAZ). The WNZ showed highest corrosion resistance due to the fine recrystallized grains, the dissolution of T1(Al2CuLi) phase, and the refined and evenly-distributed particles in this area. However, the HAZ had the lowest corrosion resistance due to the intergranular precipitates, deleterious precipitate-free zone (PFZ), S′ (Al2CuMg) phase, and the galvanic corrosion couples formed among T1, θ′, and PFZ.

scholarly journals Effect of Sn Addition on Microstructure and Corrosion Behavior of As-Extruded Mg–5Zn–4Al Alloy

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2069 ◽  
Author(s):  
Jian Ding ◽  
Xin Liu ◽  
Yujiang Wang ◽  
Wei Huang ◽  
Bo Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Corrosion Current ◽  
Electrochemical Measurements ◽  
Corrosion Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Average Grain Size

The effect of Sn addition on the microstructure and corrosion behavior of extruded Mg–5Zn–4Al–xSn (0, 0.5, 1, 2, and 3 wt %) alloys was investigated by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical measurements, and immersion tests. Microstructural results showed that the average grain size decreased to some degree and the amount of precipitates increased with the increasing amount of Sn. The extruded Mg–5Zn–4Al–xSn alloy mainly consisted of α-Mg, Mg32(Al,Zn)49, and Mg2Sn phases as the content of Sn was above 1 wt %. Electrochemical measurements indicated that the extruded Mg–5Zn–4Al–1Sn (ZAT541) alloy presented the best corrosion performances, with corrosion potential (Ecorr) and corrosion current density (Icorr) values of −1.3309 V and 6.707 × 10−6 A·cm−2, respectively. Furthermore, the corrosion mechanism of Sn is discussed in detail.

Transmission Electron Microscopy of Corrosion of Stainless Steel-Zirconium Metal Waste Forms

1999 ◽  
Vol 5 (S2) ◽  
pp. 848-849
Author(s):  
J.S. Luo ◽  
D.P. Abraham
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Corrosion Behavior ◽  
Spent Nuclear Fuel ◽  
Intermetallic Phase ◽  
Fission Products ◽  
Microstructural Characterization ◽  
Waste Forms ◽  
Transmission Electron

Stainless steel-zirconium (SS-Zr) alloys have been developed as waste forms to immobilize and retain fission products generated during the electrometallurgical treatment of spent nuclear fuel. The baseline waste form is a stainless steel-15 wt.% zirconium (SS-15Zr) alloy, which is prepared by melting appropriate amount of Type 316 stainless steel (SS316) and high purity zirconium. As zirconium has very low solubility in iron, the addition of zirconium to SS316 results in the formation of ZrFe2 -type Laves intermetallic phases. The corrosion behavior of stainless steel has been widely studied; however, the corrosion behavior of the Zr-based-intermetallic has not been previously investigated. In this paper, we present a microstructural characterization of the corrosion layer formed on the Zr-intermetallic phase using energy-filtering transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS).Specimens of SS-15Zr alloy, crushed to 75 to 150 μm sizes, were immersed in 90°C deionized water for a period of two years.

The Application of Atom-Probe Techniques in Materials Science and Technology

1981 ◽  
Vol 39 ◽  
pp. 12-15
Author(s):  
Brian Ralph ◽  
A.R. Waugh ◽  
S.A. Hill ◽  
M.J. Southon ◽  
M.P. Thomas
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Atom Probe ◽  
Original Form ◽  
Surface Process ◽  
Fine Scale ◽  
Probe Field ◽  
Transmission Electron ◽  
Field Ion Microscope ◽  
Imaging Atom Probe

This brief review attempts to summarize the main uses to which the atom-probe field-ion microscope and its variants have been put in the examination of materials. No attempt is made to produce a comprehensive list of all the studies made to date, rather the type of application is illustrated from recent studies.The original form of the field-ion microscope was really limited to the acquisition of geometrical and crystallographic information on the fine scale distribution of defects and phases (e.g. 1). Even in these early applications, the study proved considerably more fruitful when other microstructural techniques, such as transmission electron microscopy, were applied in parallel. The advent of the atom-probe (AP) and imaging atom-probe (IAP) instruments allowed precise microchemical information to be obtained and these instruments have now been used for a number of detailed investigations of materials. In the main, these have divided into (I) studies of surface process and films (e.g. 2) and (II) investigations of phase distributions and segregation in the bulk (e.g. 3).

Improved Paint Baking Response of a Novel Al-Mg-Si Alloy Automotive Body Panels by Adding Zn Element and Pre-Ageing Matching

2014 ◽  
Vol 783-786 ◽  
pp. 509-514
Author(s):  
Zhi Hui Li ◽  
Li Zhen Yan ◽  
Yon Gan Zhang ◽  
Xi Wu Li ◽  
Feng Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Yield Stress ◽  
Solution Treatment ◽  
Alloy Sheet ◽  
Aged Alloy ◽  
Artificial Ageing ◽  
Automotive Body ◽  
Transmission Electron ◽  
Average Grain Size

In the present work, the microstructure and properties of a novel Al-0.92Mg-0.78Si alloy with adding Zn element were investigated by electron back scattering diffraction (EBSD), transmission electron microscopy (TEM), high transmission electron microscopy (HREM), mechanical properties tests and Erichsen test. The alloy sheet was cold-rolled to about 1mm, then solution treated at 545 °C for 30mins, and immediately water quenched. After solution treatment, the alloy was pre-aged at 140 °C for 10mins. The average grain size of the alloy was about 20μm. The yield stress and elongation of pre-aged alloy was 137MPa and 30% respectively. The IEvalue of the alloy was 8.6mm. After paint baking at 170 °C for 30mins, the increment of yield stress was about 100MPa. The GP(II) zones were formed in the alloy during paint baking process through adding Zn element, which should play a very important role for improving paint hardening response significantly. GP(II) zones and η ́ phases were formed after artificial ageing at 170 °C for 10h.

The Effect of Thermo-Mechanical Coupling on Microstructures and Tensile Properties of Al-Li 2198-T8 Alloy via Friction Spot Welding

2016 ◽  
Vol 879 ◽  
pp. 1200-1206
Author(s):  
Chong Gao ◽  
Yue Ma ◽  
Yan Ling Pei ◽  
Shu Suo Li ◽  
Ji Zhong Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tensile Properties ◽  
Spot Welding ◽  
Alloy Sheet ◽  
Original Material ◽  
X Ray Diffraction ◽  
Mechanical Coupling ◽  
Friction Spot Welding ◽  
Transmission Electron ◽  
Coupling Zone

Al-Li 2198-T8 alloy sheet was processed by friction spot welding (FSpW). The microstructures and tensile properties of FSpW 2198-T8 alloy were studied by means of optical microscopy (OM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile testing. The results show that the grain size of Al-Li 2198-T8 alloy processed by FSpW was refined with the strengthening precipitates dissolved into Al matrix and dislocation density decreased. Hence, the plasticityin thermo-mechanical coupling zone (TMCZ) of FSpW 2198-T8 alloy was improved, while the yield strength (YS) of TMCZ zone was lower than the original material (239 MPa <470 MPa). In addition, the strengthening mechanisms of different zones of FSpW 2198-T8 alloy were estimated.

Microstructural change and corrosion variation of SAPH440 steel induced by pre-deformation

2019 ◽  
Vol 9 (6) ◽  
pp. 610-615
Author(s):  
Shuo Weng ◽  
Hongchang Cai ◽  
Lihui Zhao ◽  
Songlin Zheng
Keyword(s):  
Electron Microscopy ◽  
Tensile Elongation ◽  
Corrosion Current ◽  
Open Circuit ◽  
Corrosive Solution ◽  
Microstructure Observation ◽  
Transmission Electron ◽  
Weight Loss Method ◽  
Corrosion Susceptibility ◽  
Loss Method

The influence of microstructural variation on corrosion of SAPH440 steel induced by pre-deformation has been investigated in the corrosive solution. The microstructure observation was carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The corrosion was characterized by weight loss method (WLM), open circuit potential (OCP) and potentiodynamic polarization curve (PPC) measurements. The results show that compared to the as-received specimens, the corrosion potential moves to the negative direction and corrosion current density increases after pre-deformation. The corrosion susceptibility is enhanced by the pre-deformation behavior, which is attributed to the increase in dislocation density with the increasing tensile elongation.

scholarly journals Fabrication of p-NiO/n-TiO2 Solar Device for Photovoltaic Application

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
R. T. Mouchou ◽  
K. O. Ukoba ◽  
O. T. Laseinde ◽  
T. C. Jen
Keyword(s):  
Electron Microscopy ◽  
Solar Cells ◽  
Energy Demand ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
Photovoltaic Application ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
And Performance ◽  
P Type

Energy demand is increasing globally owing to population growth. Solar cell development has gained considerable attention because of its potential to provide everyone with sustainable, affordable, clean, and globally accessible energy. A heterojunction solar device for photovoltaic applications was developed in this study, using nickel oxide (NiO) as the p-type and titanium oxide (TiO2) as the n-type. The material chosen was motivated by the affordability, availability, and performance compared to existing silicon that is more efficient but less affordable and available. The TiO2 and NiO2 were synthesised and characterised before the deposition and characterisation of the solar cells. The characterisation was carried out using Fourier transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM), scanning electron microscopy (SEM), EDX, X-ray Diffraction (XRD), and a four-point probe. The deposition parameters were fine-tuned to achieve optimum optoelectronic properties for the solar device. The final device exhibited an open-circuit voltage of 370 mV, a current density of 1.7 mA, and solar cells efficiency of 3.7.

In-Situ Electromigration Stressing in Transmission Electron Microscopy for Al-Cu Interconnects

1994 ◽  
Vol 356 ◽  
Author(s):  
W. C. Shih ◽  
A.L. Greer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Open Circuit ◽  
Grain Structure ◽  
Cu Interconnects ◽  
Early Stress ◽  
Transmission Electron ◽  
Copper Depletion

AbstractUnpassivated 2.1 μm wide Al-4wt%Cu interconnects with near-bamboo grain structure, are electromigration-tested to failure in-situ in transmission electron microscopy. Early stress-induced voids stop growing and are not fatal. Hillocking is associated with precipitates, fatal voiding with copper depletion. Electromigration-induced voids form at the upstream end of inclined grain boundaries. Healing events are analysed and it is shown that open-circuit failure can occur when the proximity of grain boundaries impairs the stress-driven healing.

scholarly journals Rapid In Vitro Corrosion Induced by Crack-Like Pathway in Biodegradable Mg–10% Ca Alloy

2013 ◽  
Vol 19 (S5) ◽  
pp. 210-214 ◽  
Author(s):  
Jae-Young Jung ◽  
Sang-Jun Kwon ◽  
Hyung-Seop Han ◽  
Gui Fu Yang ◽  
Ji-Young Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Corrosion Behavior ◽  
Binary Alloy ◽  
Lamellar Structure ◽  
Corrosion Mechanism ◽  
Transmission Electron

AbstractThe in vitro corrosion mechanism of the biodegradable cast Mg–10% Ca binary alloy in Hanks' solution was evaluated through transmission electron microscopy observations. The corrosion behavior depends strongly on the microstructural peculiarity of Mg2Ca phase surrounding the island-like primary Mg phase and the fast corrosion induced by the interdiffusion of O and Ca via the Mg2Ca phase of lamellar structure. At the corrosion front, we found that a nanosized crack-like pathway was formed along the interface between the Mg2Ca phase and the primary Mg phase. Through the crack-like pathway, O and Ca are atomically exchanged each other and then the corroded Mg2Ca phase was transformed to Mg oxides. The in vitro corrosion by the exchange of Ca and O at the nanosized pathway led to the rapid bulk corrosion in the Mg–Ca alloys.

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