scholarly journals Effect of sensitization on corrosion properties of TIG welded Al-Mg alloy

2020 ◽  
Vol 70 (1) ◽  
pp. 47-51
Author(s):  
Ljubica Radović ◽  
Jelena Marinković
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mass Loss ◽  
Grain Boundaries ◽  
Base Metal ◽  
Intergranular Corrosion ◽  
Corrosion Properties ◽  
Rich Phase ◽  
Hot Rolled ◽  
Scanning Electron

The effect of sensitization on the intergranular corrosion (IGC) of TIG welded AlMg6Mn was investigated by means of scanning electron microscopy (SEM) and corrosion NAMLT tests. The as-received hot rolled AlMg6Mn alloy plates with a thickness of 8 mm were welded by TIG welding with S-AlMg5 as a filler material. Specimens were sensitized at 100°C for 7 days. It was found that welded specimens are sensitive to IGC. The. mass loss in NAML test was 106.7 mg/cm². The welding increases the susceptibility to IGC, since the mass loss of the base metal at the same test was 70.7 mg/cm². The increase of susceptibility to IGC is attributed to significant continually precipitated Mg-rich phase along the grain boundaries during the sensitization treatment.

Effect of Pre-Rolling Reduction on Intergranular Corrosion of Aluminum Alloy 2519A

2007 ◽  
Vol 546-549 ◽  
pp. 1117-1122 ◽  
Author(s):  
Y. Liu ◽  
Xin Ming Zhang ◽  
B. Liu ◽  
Hui Zhong Li ◽  
Hui Gao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminum Alloy ◽  
Grain Boundaries ◽  
Intergranular Corrosion ◽  
Discrete Distribution ◽  
Rolling Reduction ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Scanning Electron

The effect of pre-rolling reduction prior to ageing on the size and distribution of the precipitates, the width of precipitation free zones (PFZ) along grain boundaries and intergranular corrosion (IGC) of aluminum alloy 2519A were investigated by hardness tests, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results showed that the time for peak-age shortened when the reduction increased, which resulted in refining the precipitatates and distributing homogeneously within the grains and hence the IGC decreased. With increasing pre-rolling reduction, the PFZ along grain boundaries became narrower and precipitates changed from continuous chains to discrete distribution, which resulted in high IGC resistance.

scholarly journals Continuous Cooling Transformation Diagrams of 2.25Cr-1Mo-0.25V Submerged-Arc Weld Metal and Base Metal

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1055
Author(s):  
Hannah Schönmaier ◽  
Bernd Loder ◽  
Thomas Fischer ◽  
Fred Grimm ◽  
Ronny Krein ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Weld Metal ◽  
Base Metal ◽  
Lower Bainite ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Upper Bainite ◽  
Cct Diagrams ◽  
Scanning Electron

The transformation behavior and microstructural evolution during continuous cooling within the heat affected zone between the weld beads of a 2.25Cr-1Mo-0.25V all-weld metal and the corresponding 2.25Cr-1Mo-0.25V base metal were investigated by means of dilatometer measurements, optical and scanning electron microscopy. Furthermore, macro-hardness measurements were conducted and the ferrite phase fraction was analyzed from optical microscopic images using an imaging processing program. Thereupon a continuous cooling transformation (CCT) diagram for the 2.25Cr-1Mo-0.25V base metal and three welding CCT diagrams with different peak temperatures were constructed to realistically simulate the temperature profile of the different regions within the heat affected zones between the weld beads of the multi-layer weld metal. The microstructural constituents which were observed depending on the peak temperature and cooling parameters are low quantities of martensite, high quantities of bainite and in particular lower bainite, coalesced bainite and upper bainite as well as ferrite for the welding CCT diagrams. Regarding the base metal CCT diagram, all dilatometer specimens exhibited a fully bainitic microstructure consisting of lower bainite, coalesced bainite and upper bainite. Only the slowest cooling rate with a cooling parameter of 50 s caused a ferritic transformation. Nevertheless, it has to be emphasized that the distinction between martensite and bainite and the various kinds of bainite was only possible at higher magnification using scanning electron microscopy.

Effects of Homogenization-Free on the Microstructures of an Al-Mg-Si-Cu Hot-Rolled Plate for Automotive Pannel

2018 ◽  
Vol 941 ◽  
pp. 1529-1534
Author(s):  
Ni Tian ◽  
Qi Long Liu ◽  
Zi Yan Zhao ◽  
Gang Zhao ◽  
Kun Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminum Alloy ◽  
Rolling Direction ◽  
Rolled Plate ◽  
Alloy Plate ◽  
Solution Treated ◽  
Aluminum Alloy Plate ◽  
Hot Rolled ◽  
Scanning Electron

The microstructure of Al-1.01Mg-1.11Si-0.38Cu-0.69Mn aluminum alloy plate hot-rolled from homogenization and homogenization-free ingots were investigated by optical microscopy and scanning electron microscopy assisted with energy dispersive spectroscopy (SEM/EDS). The results showed that there are 3 main kinds of constituents such as Mg2Si, AlCuMgSi and AlFeMnSi in the as-cast Al-1.01Mg-1.11Si-0.38Cu-0.69Mn aluminum alloy ingot. After homogenization treated at 545°C for 24h, the black Mg2Si and the white bright AlCuMgSi particles in the ingot dissolved into matrix, but the grey AlFeMnSi phase partly dissolved, contracted into sphere and become coarse, many ultrafine dispersoids appear in the dendritic arms. The constituents in the plates hot-rolled from the homogenization and homogenization-free ingots are both distributed as broken chains along the rolling direction. However, compared with the particles configuration in the plate that hot-rolled from homogenization ingot, the particles in the plate that hot-rolled from the homogenization-free ingot are finer, more numerous and more homogenous, and with insufficient recrystallization when the plates are solution treated at 545°C for 2 h and then water quenched.

Effect of Cooling Rate on the Microstructure of Cu80Cr20 Alloys

2011 ◽  
Vol 694 ◽  
pp. 704-707
Author(s):  
Z.M. Zhou ◽  
W.J. Huang ◽  
J. Luo ◽  
X.P. Li ◽  
T. Zhou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cooling Rate ◽  
Electromagnetic Levitation ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Rich Phase ◽  
Arc Melting ◽  
Splat Quenching ◽  
Scanning Electron

The effect of cooling rate on the microstructure of Cu80Cr20 alloys was studied by using vacuum non-consumable arc melting, vacuum induction melting, electromagnetic levitation and splat quenching. The microstructure evolution of the Cr-rich were analyzed by scanning electron microscopy (SEM) and optical microscopy. The results showed that nonuniform Cr-rich dendrite distributes on Cu-rich matrix for arc melted alloys and uniform Cr-rich dendrite distributes on Cu-rich matrix for electromagnetic levitation melted alloys and vacuum induction melted alloys. However, the Cr-rich phase show both dendrites and spheroids for splat quenched alloys. This means liquid phase separation occurred during rapid solidification.

Anti-Corrosion Properties of Composite WC-Ni Based Brazing Coatings

2011 ◽  
Vol 347-353 ◽  
pp. 1605-1608
Author(s):  
Da Quan Zhang ◽  
Li Xin Gao ◽  
Huan Wu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
316L Stainless Steel ◽  
Vacuum Furnace ◽  
Corrosion Properties ◽  
Mixed Powder ◽  
Weight Loss Method ◽  
Loss Method ◽  
Superior Corrosion Resistance ◽  
Scanning Electron

The flexible metallic cloth was made of mixed powder consisting of WC and organic blend. A brazing coating was obtained through the high temperature brazing of the metallic cloth in vacuum furnace. The anti-corrosion of the brazing coating was investigated by weight-loss method and electrochemical measurements. The surface morphology observation was conducted by the scanning electron microscopy (SEM). The results show that the composite coating has superior corrosion resistance compared with 316L stainless steel.

scholarly journals Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1515
Author(s):  
Halyna Klym ◽  
Ivan Karbovnyk ◽  
Andriy Luchechko ◽  
Yuriy Kostiv ◽  
Viktorija Pankratova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Grain Boundaries ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Spectroscopy Technique ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Scanning Electron

BaGa2O4 ceramics doped with Eu3+ ions (1, 3 and 4 mol.%) were obtained by solid-phase sintering. The phase composition and microstructural features of ceramics were investigated using X-ray diffraction and scanning electron microscopy in comparison with energy-dispersive methods. Here, it is shown that undoped and Eu3+-doped BaGa2O4 ceramics are characterized by a developed structure of grains, grain boundaries and pores. Additional phases are mainly localized near grain boundaries creating additional defects. The evolution of defect-related extended free volumes in BaGa2O4 ceramics due to the increase in the content of Eu3+ ions was studied using the positron annihilation lifetime spectroscopy technique. It is established that the increase in the number of Eu3+ ions in the basic BaGa2O4 matrix leads to the agglomeration of free-volume defects with their subsequent fragmentation. The presence of Eu3+ ions results in the expansion of nanosized pores and an increase in their number with their future fragmentation.

scholarly journals Enhancement the Osseo Integration Properties of Polymer for Human Body Implants

2020 ◽  
Vol 23 (4) ◽  
pp. 331-337
Author(s):  
Dhurgham Majid Rasheed ◽  
Dunya Abdulsahib Hamdi
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Grain Boundaries ◽  
Mechanical Performance ◽  
Wear Test ◽  
High Energy ◽  
In Vitro Test ◽  
Scanning Electron

In this research, polymer polymethyl methacrylate PMMA composite with nano ceramic Zr and HAp material were used to manufacture one part of the implant system (femoral ball head of hip implant). Three set of hybrid materials were fabricated and tested for this study; the first mixtures which contains 100% (PMMA), the second mixtures which contains (90% (PMMA) + 8% (Zr) + 2% (HAp)), and the third mixtures which contains (80% (PMMA) + 18% (Zr) + 2% (HAp)) were investigated. The mechanical properties for these mixtures increased with the increasing of nano ceramic concentration (Zr and HAp) composite material in the polymer compared to pure polymer PMMA sample. However, an increase in the concentration of Zr from 8% to 18% content cause a considerable decrease of the hardness where a drop of homogeneity in Zr- matrix PMMA contact occurred, V Hardness value are (68 ,80 and 70) Kg.mm for three mixture respectively. The wear test was in agreement with results of the hardness test. The weight loss of the above samples of the wear test were (0.041, 0.035 and 0.037) respectively. According to mechanical properties, the best sample contains (90% (PMMA) + 8% (Zr) + 2% (HAp)). The Scanning electron microscopy resolute showed the particles forming semi-continuous network along grain boundaries polymer for second sample mixtures containing (90% (PMMA) + 8% (Zr) + 2% (HAp)), provides a low atomic packing and high energy. This will make the grain boundaries more reactive and strengthen mechanical performance. The Optical microscopy, Scanning electron microscopy and Xray spectroscopy analysis for In vitro test using SBF shows the growth of HAp layer with an increase in concentration of Ca and P elements formed on the surface of the second sample. This display of good results is a proof of the biocompatibility of the polymer sample.

Effect of Mesostructural Elements on Radiation-Induced Porosity in 16Cr-19Ni-2Mo-2Mn-Nb-Ti-V-P-B Austenitic Steel

2019 ◽  
Vol 946 ◽  
pp. 357-361
Author(s):  
Vladimir I. Pastukhov ◽  
Irina A. Portnykh ◽  
Mikhail L. Lobanov
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Boundaries ◽  
Austenitic Steel ◽  
Neutron Irradiation ◽  
Steel Structure ◽  
Void Size ◽  
Orientation Microscopy ◽  
Radiation Induced ◽  
Scanning Electron

Different mesostructural elements of 16Cr-19Ni-2Mo-2Mn-Nb-Ti-B austenitic steel have been examined after neutron irradiation to damage dose up to 82 dpa by scanning electron microscopy using orientation microscopy (EBSD). Radiation porosity with maximum void size up to 200 nm was observed in austenitic steel structure after neutron irradiation. Nonuniformity, related to mesostructural elements, such as general grain boundaries, special CSL boundaries Σ3 (twins), areas with high density of low-angle boundaries, is typical for radiation porosity.

Effect of Ti and Sb Elements Addition on the Microstructure and Corrosion Resistance of Hot-Dip Galvanized Zn-11Al-3Mg Alloy

2021 ◽  
Vol 1035 ◽  
pp. 630-637
Author(s):  
Hui Jie Sun ◽  
Guo Rong Zhou ◽  
Ming Ming Zhang ◽  
Xue Feng Wang ◽  
Shui Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Energy Dispersive Spectrometry ◽  
X Ray Diffraction ◽  
Rich Phase ◽  
X Ray ◽  
Pitting Corrosion Resistance ◽  
Scanning Electron

The effect of Ti and Sb elements addition on the microstructures and corrosion resistance of hot-dip galvanized Zn-11Al-3Mg alloy was investigated by scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and Electrochemical workstation, respectively. Results showed that the grain size of the alloy was obviously refined with the addition of Ti and Sb elements, due to Al3Ti phase as the nucleation substrate resulted in the transformation of Al-rich phase from dendrite to petal-like. In addition, the pitting corrosion resistance of the alloy has been significantly enhanced.

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