Grains Ultra-Refinement of Materials Imposed by Pulse Laser

2006 ◽  
Vol 315-316 ◽  
pp. 770-774
Author(s):  
Ming Zhou ◽  
X.Q. Zhu ◽  
Q.X. Dai ◽  
Lan Cai
Keyword(s):  
Electron Microscopy ◽  
Steel Sample ◽  
Stainless Steel Sample ◽  
Laser Shock Processing ◽  
Black Paint ◽  
Gaussian Profile ◽  
Transmission Electron ◽  
Dynamic Yield Strength ◽  
Dynamic Yield ◽  
Profile Vector

Submicron-sized top layer was synthesized on an austenitic stainless steel sample by adopting laser shock processing (LSP). The substructures were characterized and examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), moreover, the mechanism of ultra-refinement laser-induced was analyzed. It showed that a refined top surface with average subgrains size of 0.5(m was synthesized by the model of single laser loading, black paint as absorption coating and the peak pressure induced by LSP approximating twice of the dynamic yield strength of target. It indicated that thermoplastic destabilization had happened in heavily localized regions imposed by LSP. Streak-like subgrains were oriented perpendicular to shock wave (Gaussian profile) vector. In order to accommodate plastic strain, streak-like subgrains experienced necking, breaking up and dynamic rotational recrystallization, as a result, the submicron grains were formed on the surface of sample.

scholarly journals Sample Preparation Methodologies for In Situ Liquid and Gaseous Cell Analytical Transmission Electron Microscopy of Electropolished Specimens

2016 ◽  
Vol 22 (6) ◽  
pp. 1350-1359 ◽  
Author(s):  
Xiang Li Zhong ◽  
Sibylle Schilling ◽  
Nestor J. Zaluzec ◽  
M. Grace Burke
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Focused Ion Beam ◽  
General Procedure ◽  
Ion Beam ◽  
Metals And Alloys ◽  
Stainless Steel Sample ◽  
Transmission Electron ◽  
Wide Range

AbstractIn recent years, an increasing number of studies utilizing in situ liquid and/or gaseous cell scanning/transmission electron microscopy (S/TEM) have been reported. Because of the difficulty in the preparation of suitable specimens, these environmental S/TEM studies have been generally limited to studies of nanoscale structured materials such as nanoparticles, nanowires, or sputtered thin films. In this paper, we present two methodologies which have been developed to facilitate the preparation of electron-transparent samples from conventional bulk metals and alloys for in situ liquid/gaseous cell S/TEM experiments. These methods take advantage of combining sequential electrochemical jet polishing followed by focused ion beam extraction techniques to create large electron-transparent areas for site-specific observation. As an example, we illustrate the application of this methodology for the preparation of in situ specimens from a cold-rolled Type 304 austenitic stainless steel sample, which was subsequently examined in both 1 atm of air as well as fully immersed in a H2O environment in the S/TEM followed by hyperspectral imaging. These preparation techniques can be successfully applied as a general procedure for a wide range of metals and alloys, and are suitable for a variety of in situ analytical S/TEM studies in both aqueous and gaseous environments.

Nanostructured 316 Stainless Steel Prepared under Traction by Surface Mechanical Attrition Treatment

2009 ◽  
Vol 614 ◽  
pp. 201-206
Author(s):  
Xiao Fang Yang ◽  
Jian Lu
Keyword(s):  
Stainless Steel ◽  
Optical Microscope ◽  
Steel Sample ◽  
Surface Mechanical Attrition Treatment ◽  
Stainless Steel Sample ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Nanostructured Layer ◽  
Nanoindentation Measurement ◽  
Measurement Results

A nanostructured 316 austenitic stainless steel sample was prepared under traction using a new surface mechanical attrition treatment (SMAT) system. The microstructure of the surface layer of the SMATed sample was characterized using an optical microscope and transmission electron microscope (TEM). Microhardness on the cross-section was investigated by nanoindentation measurement. Results showed that a deeper nanostructured layer was obtained in comparison with that of the sample SMATed without traction.

The Mechanism and Experimental Study on Laser Peen Forming of Sheet Metal

2006 ◽  
Vol 315-316 ◽  
pp. 607-611 ◽  
Author(s):  
Jian Zhong Zhou ◽  
Yong Kang Zhang ◽  
Xing Quan Zhang ◽  
Chao Jun Yang ◽  
Hui Xia Liu ◽  
...  
Keyword(s):  
Shock Waves ◽  
Sheet Metal ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Steel Sheets ◽  
Peen Forming ◽  
Plastic Forming ◽  
Dynamic Yield Strength ◽  
Dynamic Yield ◽  
Shock Processing

Laser peen forming of sheet metal is a new plastic forming technique based on laser shock waves, which derives from the combination of laser shock processing and conventional shot peening technique, it uses high-power pulsed laser replacing the tiny balls to peen the surface of sheet metal, when the laser induced peak pressure of shock waves exceeds the dynamic yield strength of the materials, the sheet metal yields, resulting in an inhomogeneous residual stresses distribution in depth. The sheet metal responds to this residual stress by elongating at the peened surface and effectively bending the overall shape. On the basis of analyzing the mechanism of laser peen forming, the line-track-peening experiments of 45 steel sheets with 2 mm thickness were carried out; a curved sheet metal with deep layer of residual compressive stress was obtained. The preliminary experiment result shows that laser peen forming can offer desirable characteristics in shaped metals and is a valuable technique for producing components for a range of industries.

SEM and TEM Microstructure Characterization of a Commercial Purity Aluminum after Laser Treatment

2012 ◽  
Vol 186 ◽  
pp. 323-326
Author(s):  
Magdalena Rozmus-Górnikowska ◽  
Łukasz Major ◽  
Jerzy Morgiel
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Laser Treatment ◽  
Pulse Mode ◽  
Laser Shock Processing ◽  
Transmission Electron ◽  
Tem Microstructure ◽  
Commercial Purity Aluminum ◽  
Shock Processing

The effect of the Laser Shock Processing (LSP) on the microstructure of the surface layer of a commercially pure alluminum was studied. LSP process was performed with a high-power Q-switched Nd:YAG ReNOVALaser, operating in a pulse mode (18 ns), with a power density of 0,43 GW/cm2. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and a Scanning Transmision Electron Microscopy (STEM) have been used to study the microstructure of the surface layer of the investigated material after laser treatment. SEM investigation showed that after LSP process surface melting occurs but is restricted to a thin layer. However, both TEM and STEM images indicate that under the thin melting layer a high density of dislocations were visible. It has been found that the laser beam with employing parameters caused plastic deformation of the surface layer of the investigated aluminum.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Transmission Electron Microscopy Studies of Pore Cells in Limax Maximus

1977 ◽  
Vol 35 ◽  
pp. 656-657
Author(s):  
B. S. Beltz
Keyword(s):  
Electron Microscopy ◽  
Cell Periphery ◽  
Salivary Duct ◽  
Terrestrial Mollusc ◽  
Buccal Ganglia ◽  
Transmission Electron ◽  
Pore Cells ◽  
Gland Tissue ◽  
Storage Area ◽  
Limax Maximus

The cells which are described in this study surround the salivary nerve of the terrestrial mollusc, Limax maximus. The salivary system of Limax consists of bilateral glands, ducts, and nerves. The salivary nerves originate at the buccal ganglia, which are situated on the posterior face of the buccal mass, and run along the salivary duct to the gland. The salivary nerve branches several times near the gland, and eventually sends processes into the gland.The pore cells begin to appear at the first large branch point of the salivary nerve, near the gland (Figure 1). They follow the nerve distally and eventually accompany the nerve branches into the gland tissue. The cells are 20-50 microns in diameter and contain very small nuclei (1-5 microns) (Figure 2).The cytoplasm of the pore cells is segregated into a storage area of glycogen and an organelle region located in a band around the cell periphery (Figure 3).

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