scholarly journals Effect of Ultrasonic Surface Rolling Treatment on Corrosion Behavior of Alloy 690

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 917 ◽  
Author(s):  
Jiang Liu ◽  
Junbiao Liu ◽  
Xuehui Zhang ◽  
Tahir Ahmad ◽  
Tongxiang Liang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Coarse Grained ◽  
Alloy 690 ◽  
Average Grain Size ◽  
Before And After ◽  
Immersion Experiment ◽  
Secondary Side

The nanograins (NG) on the top surface layer of alloy 690 were successfully prepared by ultrasonic surface rolling treatment (USRT). The average grain size of NG alloy 690 was 55 nm, and the thickness of the NG surface layer was about 1 μm. Meanwhile, the surface roughness was significantly reduced after surface nanocrystalliztion. The corrosion behavior of alloy 690 before and after USRT was studied in a secondary side environment containing chloride. Electrochemical corrosion experiments demonstrated that the passive film generated by USRT was denser than that formed on coarse-grained (CG) alloy 690. Pitting corrosion was prone to occur in grain boundaries of CG alloy 690, and the pits on the surface of NG alloy 690 were smaller than those generated on CG alloy 690 after 1000 h of an immersion experiment.

scholarly journals Material microstructure effects in micro-endmilling of Cu99.9E

2016 ◽  
Vol 232 (7) ◽  
pp. 1143-1155 ◽  
Author(s):  
AM Elkaseer ◽  
SS Dimov ◽  
DT Pham ◽  
KP Popov ◽  
L Olejnik ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Chip Thickness ◽  
Micro Milling ◽  
Coarse Grained ◽  
Material Microstructure ◽  
Micro Cutting ◽  
Minimum Chip Thickness ◽  
Average Grain Size ◽  
Material Homogeneity

This article presents an investigation of the machining response of metallurgically and mechanically modified materials at the micro-scale. Tests were conducted that involved micro-milling slots in coarse-grained Cu99.9E with an average grain size of 30 µm and ultrafine-grained Cu99.9E with an average grain size of 200 nm, produced by equal channel angular pressing. A new method based on atomic force microscope measurements is proposed for assessing the effects of material homogeneity changes on the minimum chip thickness required for a robust micro-cutting process with a minimum surface roughness. The investigation has shown that by refining the material microstructure the minimum chip thickness can be reduced and a high surface finish can be obtained. Also, it was concluded that material homogeneity improvements lead to a reduction in surface roughness and surface defects in micro-cutting.

Effect of the Grain Size on Electrochemical Corrosion Behavior of Cu60Ni20Cr20 Alloys in Solutions Containing Chloride Ions

2012 ◽  
Vol 476-478 ◽  
pp. 16-20
Author(s):  
Guo De Li ◽  
Jing Bian ◽  
Zhong Qiu Cao ◽  
Ke Zhang ◽  
Ya Jun Fu
Keyword(s):  
Grain Size ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Coarse Grained ◽  
Protective Film ◽  
Ion Concentrations ◽  
Corrosion Rates ◽  
Electrochemical Corrosion Behavior

The two Cu60Ni20Cr20alloys with the different grain size were prepared by conventional casting (CA) and mechanical alloying (MA) through hot pressing. Effect of the grain size on electrochemical corrosion behavior of the two Cu60Ni20Cr20 alloys was also studied in solutions containing chloride ions. Results show that the free corrosion potentials of the two alloys move toward to negative values, corrosion current densities increase and therefore corrosion rates become faster with the increment of chloride ion concentrations. CACu60Ni20Cr20alloy and MACu60Ni20Cr20alloy have passive phenomena in 0.05mol/L Na2SO4 neutral solution, but passive phenomena become weak or disappear when the chloride ions are added. Corrosion rates of the nanocrystalline MACu60Ni20Cr20alloy become slower than those of the coarse grained CACu60Ni20Cr20alloy in solutions containing the same chloride ion concentrations because MACu60Ni20Cr20alloy is able to produce large concentrations of grain boundaries and passive elements is able to diffuse quickly to form the protective film.

Formation of nanophases in a Cu–Zn alloy under high current density electropulsing

2000 ◽  
Vol 15 (10) ◽  
pp. 2065-2068 ◽  
Author(s):  
W. Zhang ◽  
M. L. Sui ◽  
K. Y. Hu ◽  
D. X. Li ◽  
X. N. Guo ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Energy ◽  
Coarse Grained ◽  
High Current ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Before And After ◽  
Electropulsing Treatment ◽  
Zn Alloy

The microstructure of samples before and after a high current density electropulsing treatment was characterized by using high-resolution transmission electron microscopy. It has been found that in the coarse-grained Cu–Zn alloy subjected to the electropulsing treatment, two nanophases were formed, α–Cu(Zn) and β′–(CuZn), the average grain size of which is about 11 nm. A possible mechanism for the formation of nanophases was proposed. The experimental results indicated that electropulsing, as an instantaneous high-energy input, plays an important role in the nonequilibrium microstructural changes in materials and serves as a potential processing approach to synthesize nanostructured materials.

Study on the Structure and Properties of Surface Nanocrystallized Zr-4

2011 ◽  
Vol 415-417 ◽  
pp. 660-665
Author(s):  
Cong Hui Zhang ◽  
Da Li Liu ◽  
Xin Zhe Lan ◽  
Xi Cheng Zhao
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Processing Time ◽  
Optical Microscope ◽  
Surface Mechanical Attrition Treatment ◽  
Structure And Properties ◽  
Nanostructured Surface ◽  
Grain Sizes ◽  
Mechanical Attrition ◽  
Average Grain Size

A nanostructured surface layer was obtained on the surface of Zr-4 by surface mechanical attrition treatment(SMAT). The structure and the properties of the SMAT sample were analyzed by means of the optical microscope, hardness and polarization curve testing. The results show that， when processing time for 5min, the average grain sizes on the surface layer can be refined to 23nm. The average grain size by SMAT-ed for 15min is 20nm, which is the smallest. The microhardness have a significant increase, the surface roughness also increase, and the corrosion resistance reduce in 1mol H2SO4solution.

Nanostructured Surface Layers In Low Carbon Steel and Pure Titanium Induced By High-Speed Rotating Wire-Wheel Deformation

2010 ◽  
Vol 97-101 ◽  
pp. 1352-1355
Author(s):  
Xin Min Fan ◽  
Fei Yan Liu ◽  
Jie Wen Huang
Keyword(s):  
Surface Layer ◽  
Carbon Steel ◽  
High Speed ◽  
Pure Titanium ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
Commercially Pure Titanium ◽  
Low Carbon ◽  
Cross Sectional ◽  
Average Grain Size

A nanostructure surface layer was produced on low carbon steel and commercially pure titanium using high-speed rotating wire-wheel deformation (HRWD). The microstructural features of the surface layer were systematically characterized by cross-sectional optical microcopy observations, transmission electron microscopy, and microhadness measurement was conducted along the depth from top surface layer to matrix of the samples. The results show that nearly equiaxed nanocrystalline layer is formed on the surface of the low carbon steel and pure titanium, in which the average grain size is about 8 nm and 15 nm respectively. The microhardness of the top surface is enhanced obviously compared with that of the coarse-grained matrix.

scholarly journals Influence of parameters of deep grinding on nanohardness and surface roughness of C45 steel

Mechanik ◽  
2018 ◽  
Vol 91 (11) ◽  
pp. 1026-1028
Author(s):  
Mariusz Deja ◽  
Alicja Stanisławska ◽  
Marek Szkodo ◽  
Karolina Wszelak
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Surface Layer ◽  
Flat Surfaces ◽  
Average Grain Size

The paper presents the results of investigations on the effect of the depth of concurrent grinding of flat surfaces on the roughness and nano-hardness of the surface layer of C45 steel with a ferritic-pearlitic structure and average grain size of 20 μm. A significant increase in the hardness of the surface layer of the workpiece was obtained for all grinding depths.

scholarly journals Electrochemical Corrosion Behavior and Mechanical Properties of Nanocrystalline Ti–6Al–4V Alloy Induced by Sliding Friction Treatment

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 760
Author(s):  
Jinwen Lu ◽  
Wei Zhang ◽  
Wangtu Huo ◽  
Yongqing Zhao ◽  
Wenfang Cui ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sliding Friction ◽  
Electrochemical Corrosion ◽  
Passive Layer ◽  
Coarse Grained ◽  
High Yield ◽  
Biomedical Material ◽  
Passive Behavior ◽  
Friction Treatment ◽  
Average Grain Size

A nanograined (NG) layer with an average grain size of less than 100 nm has been successfully prepared on a Ti–6Al–4V sheet surface by sliding friction treatment (SFT). The electrochemical corrosion/passive behavior and mechanical properties of an NG Ti–6Al–4V sheet were examined in this study. A bi-layer passive film that consisted of an outer TiO2-rich layer and an inner Al2O3-rich layer was formed on either an NG or coarse-grained (CG) surface. The improved corrosion was mainly caused by the enhanced stability and thickness of the passive layer. Tensile experiments were carried out to evaluate the mechanical properties at ambient temperature. The NG Ti–6Al–4V sample exhibited the high yield strength (956 MPa) with a moderate elongation of 8%. These superior comprehensive properties demonstrated its potential as a biomedical material.

Hydration Polishing of Sapphire

2010 ◽  
Vol 102-104 ◽  
pp. 695-699 ◽  
Author(s):  
Jian Lin Wu ◽  
Wei Fang Wang ◽  
Peng Fei Gao ◽  
Dong Hui Wen
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Single Crystal ◽  
Surface Texture ◽  
Polished Surface ◽  
Micro Structure ◽  
Polishing Process ◽  
Sapphire Surface ◽  
Before And After ◽  
Single Crystal Sapphire

This paper discussed the polishing characteristic of single crystal sapphire (0001) when using 100°C vapor as polishing liquid and cedar wood as polishing pad. Surface roughness and scratch were compared before and after hydration polishing process. For 20 hours hydration polishing, both XRD and surface texture show that sapphire surface was changed in micro-structure and texture, even with minor scratch on the hydration polished surface, surface roughness could be decreased to Rt6.74 in X direction and Rt7.64nm in Y direction, it is about 2 nm surface layer was removed during hydration polishing.

Comparison of corrosion behavior between coarse grained and nano/ultrafine grained alloy 690

2016 ◽  
Vol 360 ◽  
pp. 403-408 ◽  
Author(s):  
Lv Jinlong ◽  
Liang Tongxiang ◽  
Wang Chen ◽  
Guo Ting
Keyword(s):  
Corrosion Behavior ◽  
Coarse Grained ◽  
Ultrafine Grained ◽  
Alloy 690

Effects of Rare Earth on Electrochemical Corrosion Behavior of Graphite-Like Carbon Coatings

2011 ◽  
Vol 199-200 ◽  
pp. 1978-1983
Author(s):  
Zuo Ping Wang ◽  
Peng Bo Chen ◽  
Zhong Wei Ma ◽  
Jiang Tao Yu Wen
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Surface Layer ◽  
Corrosion Behavior ◽  
Current Density ◽  
Sea Water ◽  
Electrochemical Corrosion ◽  
Form Complex ◽  
Carbon Coatings ◽  
Electrochemical Corrosion Behavior

The corrosion behavior of graphite-like carbon (GLC) coating in sea water was studied and yttrium and cerium were doped into it by using mosaic in the target of magnetron sputtering process to improve its corrosion resistance. The result shows that the GLC coating characterizes typical underfilm electrochemical corrosion in sea water. Yttrium added in chromium interlayer or yttrium and cerium added in the surface layer of the GLC coating can apparently improve the microstructure result in significantly decrease the corrosive current density. As the modifications of Y in interlayer and Y, Ce and Ta in top layer are composed together to form complex GLC coating, the wear resistance and the antifriction is dramatically improved, the corrosive current density is only one-twenty fourth of that of the commercial C/Cr GLC coating.

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