Failure Behavior of Anodized Coating-Magnesium Alloy Substrate Structures

2004 ◽  
Vol 261-263 ◽  
pp. 363-368 ◽  
Author(s):  
Xi Shu Wang ◽  
Xi Qiao Feng ◽  
Xing Wu Guo
Keyword(s):  
Electron Microscope ◽  
Magnesium Alloy ◽  
Crack Initiation ◽  
Scanning Electron Microscope ◽  
Void Nucleation ◽  
Failure Behavior ◽  
Sem Images ◽  
Bulk Substrate ◽  
Bending Loading ◽  
Scanning Electron

This work focuses on the damage mechanisms and the resulting failure behavior of structures made of anodized coatings on magnesium alloy substrates. The failure of anodized coatings of about 30µm thickness on AZ91D substrates was investigated under three-points bending loading with online scanning electron microscope (SEM) observations. The obtained SEM images show that void nucleation and crack initiation occurs mainly at sites near the coating-substrate interface, and the evolutionary microcracking damage diffuses from the interface to the coating surface and also to the bulk substrate with the increasing in loading.

scholarly journals Influence of Multi-Holes on Fatigue Behaviors of Cast Magnesium Alloys Based on In-Situ Scanning Electron Microscope Technology

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1700 ◽  
Author(s):  
Xi-Shu Wang ◽  
Chang-Hao Tan ◽  
Juan Ma ◽  
Xiao-Dong Zhu ◽  
Qing-Yuan Wang
Keyword(s):  
Fatigue Crack ◽  
Electron Microscope ◽  
Crack Initiation ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Mg17al12 Phase ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium ◽  
Scanning Electron

The low cycle fatigue tests on the crack initiation and propagation of cast magnesium alloys with two small holes were carried out by using in-situ scanning electron microscope (SEM) observation technology. The fatigue crack propagation behaviors and fatigue life, which are affected by two small artificial through holes, including the distances between two holes and their locations, were discussed in detail based on the experimental results and the finite element analysis (FEA). The results indicated that the fatigue multi-cracks occurred chiefly at the edges of two holes and the main crack propagation was along the weak dendrite boundary with the plastic deformation vestiges on the surface of α-Mg phase of cast AM50 and AM60B alloys. The fatigue cracking characteristics of cast AZ91 alloy depended mainly on the brittle properties of β-Mg17Al12 phase, in which the multi-cracks occurred still at the edges of two holes and boundaries of β-Mg17Al12 phase. The fatigue crack initiation position of cast magnesium alloys depends strongly on the radius of curvature of through hole or stress concentration factor at the closed edges of two through holes. In addition, the fatigue multi-cracks were amalgamated for the samples with titled 45° of two small holes of cast Mg-Al alloys when the hole distance is less than 4D (D is the diameter of the small hole).

Characteristics of Hot Ductility and Fracture in Micro-Alloyed Q345B Structural Steel

2011 ◽  
Vol 194-196 ◽  
pp. 150-156 ◽  
Author(s):  
Fang Dong ◽  
Cheng Su ◽  
Yuan Yuan Bai
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Continuous Casting ◽  
Structural Steel ◽  
Void Nucleation ◽  
Hot Ductility ◽  
Strain Rates ◽  
Casting Condition ◽  
Temperature Range ◽  
Scanning Electron

Hot-ductility tests of the microalloyed Q345B structural steel were performed in a tensile machine of Gleeble-1500D at different strain rates of 1.5•10-3/s 、2.5•10-3/s and 2•10-2/s and at temperature range from 1300°C to 700°C(Δ T=100°C ), which are close to the continuous casting condition of steel. Fracture surfaces were examined using a scanning electron microscope; it was found that the hot decrease as strain rate decrease, because the void growth mechanism predominates over void nucleation, giving time for nucleation cracks to grow. The minimum ductility was found at about 800°C for the strain rates of 1.5•10-3/s and 2.5•10-3/s, and the fracture was intergranular. The steel has good plasticity in temperature range from 1200°C to 900°C which is suitable for straighten operation.

Local Investigation of Microstructure-Induced Fatigue Damaging

2009 ◽  
Vol 417-418 ◽  
pp. 521-524
Author(s):  
Michael Marx ◽  
Wolfgang Schäf ◽  
Markus T. Welsch ◽  
Horst Vehoff
Keyword(s):  
Electron Microscope ◽  
Crack Initiation ◽  
Scanning Electron Microscope ◽  
Crack Propagation ◽  
Focused Ion Beam ◽  
Fatigue Cracks ◽  
Ion Beam ◽  
Short Crack ◽  
Beam Technique ◽  
Scanning Electron

From the emission of dislocations till short crack propagation fatigue is a local process determined by the microstructure. In this paper we present experiments based on refined applications of the scanning electron microscope and focused ion beam technique, which give detailed information about crack initiation and the interaction of short fatigue cracks with microstructural elements.

Thick photoresists for electroforming metallic microcomponents

2008 ◽  
Vol 222 (1) ◽  
pp. 37-42 ◽  
Author(s):  
X Wei ◽  
C-H Lee ◽  
Z Jiang ◽  
K Jiang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Current Paper ◽  
Sem Images ◽  
Advantages And Disadvantages ◽  
Uv Lithography ◽  
Electroforming Process ◽  
Electroformed Nickel ◽  
Scanning Electron

Recently, microelectroforming has been extensively applied to fabricating metallic components for sensors, actuators, and other systems. Thick photoresists are used for making micromoulds for electroforming and closely related to the quality and costs of an electroforming process. In the current paper, thick UV photoresists SU8, BPR100, and KMPR are analysed and compared in their electroforming performance of nickel microcomponents. Optimized UV lithography processes are introduced for producing micromoulds in each of the resists and scanning electron microscope (SEM) images of the moulds are presented and analysed. Then, electroformed nickel components from the micromoulds are presented. Finally, applicability of the photoresists to electroforming microcomponents is discussed. Each of the resists demonstrates advantages and disadvantages to suit different applications.

PET Depolymerization Catalyzed by Sulfates under Microwave Irradiation

2012 ◽  
Vol 550-553 ◽  
pp. 792-797 ◽  
Author(s):  
Wei Lu Zhang ◽  
Xiao Ni Shi ◽  
Xin Zhang ◽  
Chun Hua Han ◽  
Dong Zhang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Microwave Irradiation ◽  
Polyethylene Terephthalate ◽  
Sem Images ◽  
Scanning Electron

Different sulfates were used as the catalysts of polyethylene terephthalate (PET) depolymerization under microwave of 250 watts, in which ZnSO4presented the best catalysis in this reaction, and the depolymerization degree (DPD) of PET was reached to 90 %. It was found that the depolymerization was occurred simultaneously on the surface and the internal parts of PET chips by the observation of scanning electron microscope (SEM) images. In addition, DPD increased with the improvement of the polarization forces of these sulfates.

scholarly journals QUALITY REINFORCEMENT OF ELECTROPLATING ZINC COATINGSELECTRODEPOSITED FROM CYANIDE FREE ALKALINE SOLUTION BY POLYAMINE 70.000 AND POLYVINYL ALCOHOL 16.000

2018 ◽  
Vol 55 (5B) ◽  
pp. 18
Author(s):  
Truong Thi Nam
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polyvinyl Alcohol ◽  
Zinc Coating ◽  
Alkaline Solutions ◽  
Zinc Ions ◽  
Sem Images ◽  
Zinc Coatings ◽  
Scanning Electron ◽  
Good Agreement

Zinc coatings have been deposited electrochemically from cyanine free alkaline solutions containing zinc ions with the presence of polyamine 70.000 and polyvinyl alcohol at different contents. The scanning electron microscope (SEM) images showed that the size of zinc grains decreased with the presence of polyamine 70.000 and polyvinyl alcohol with smoother surface of zinc coating. The polarization measurements also revealed that the coatings with the presence of polyamine or polyvinyl alcohol possessed higher value of polarity degree. This result is in good agreement with the result obtained from SEM images.

scholarly journals Experiment on Strength and Failure Behavior of Sandstone Containing Pre-Existing Cracks Under Brazilian Compression

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaojian Cao ◽  
Han Zhang ◽  
Jun Yu ◽  
Tianchong Yu ◽  
Yuxing Qing
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Process ◽  
Experimental Results ◽  
Failure Behavior ◽  
Axial Deformation ◽  
Scanning Electron

Determination of the mechanical properties of rock containing pre-existing cracks under tension condition is of great significance to understand the failure process of rock in engineering. This paper presents the experimental results of sandstone containing pre-existing cracks under Brazilian compression. The characteristics of the microcracks were analyzed by a scanning electron microscope. The results show that the rock containing pre-existing cracks has an obvious anisotropic characteristic. When the crack inclination is 45°, the rock has the minimum tensile strength and the weakest axial deformation resistance.

Performance enhancement of Scanning Electron Microscope using a Deep Convolutional Neural Network

2022 ◽  
Author(s):  
Suresh Panchal ◽  
Unnikrishnan Gopinathan ◽  
Suwarna Datar
Keyword(s):  
Neural Network ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Convolutional Neural Network ◽  
Performance Enhancement ◽  
Deep Convolutional Neural Network ◽  
Sem Images ◽  
Scan Rate ◽  
Charging Effect ◽  
Scanning Electron

Abstract We report noise reduction and image enhancement in Scanning Electron Microscope (SEM) imaging while maintaining a Fast-Scan rate during imaging, using a Deep Convolutional Neural Network (D-CNN). SEM images of non-conducting samples without conducting coating always suffer from charging phenomenon, giving rise to SEM images with low contrast or anomalous contrast and permanent damage to the sample. One of the ways to avoid this effect is to use Fast-Scan mode, which suppresses the charging effect fairly well. Unfortunately, this also introduces noise and gives blurred images. The D-CNN has been used to predict relatively noise-free images as obtained from a Slow-Scan from a noisy, Fast-Scan image. The predicted images from D-CNN have the sharpness of images obtained from a Slow-Scan rate while reducing the charging effect due to images obtained from Fast-Scan rates. We show that using the present method, and it is possible to increase the scanning rate by a factor of about seven with an output of image quality comparable to that of the Slow-Scan mode. We present experimental results in support of the proposed method.

Synthesis and Evaluation of Benzohydrazide Derivative as a Corrosion Protector for Magnesium Alloy in 3%Nacl

2021 ◽  
Author(s):  
RAJA KALIYAPERUMAL ◽  
T.KASILINGAM
Keyword(s):  
Weight Loss ◽  
Electron Microscope ◽  
Magnesium Alloy ◽  
Scanning Electron Microscope ◽  
Alkaline Medium ◽  
Energy Dispersive ◽  
Cathodic Process ◽  
X Ray ◽  
Nyquist Plots ◽  
Scanning Electron

Abstract Inhibition action of 4-Chloro-N(3,4,5-trimethoxybenzilidene) benzohydrazide on the corrosion of magnesium alloy in alkaline medium was investigated by weight-loss technique, Nyquist spectra, Tafel plot, scanning electron microscope and energy dispersive x-ray analysis. Tafel curves of magnesium alloy showed both anodic and cathodic process suppressed. Nyquist plots, scanning electron microscope and energy dispersive x-ray analysis studies provide the confirmatory evidence for the protection of magnesium alloy by the studied inhibitor.

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