Microstructural Fractal Dimension of AISI 316L Steel

1994 ◽  
Vol 367 ◽  
Author(s):  
M. Hinojosa ◽  
R. Rodréguez ◽  
U. Ortiz
Keyword(s):  
Fractal Dimension ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Tensile Strain ◽  
Optical Microscope ◽  
Standard Test ◽  
Test Method ◽  
Aisi 316L ◽  
316L Steel ◽  
Deformation Processes

AbstractFractal dimension of the microstructure of AISI 316L steel (17 Cr, 12.7 Ni, 2.1 Mo, 1. 5 Mn, 0.01 C) with different degrees of strain were obtained from Richardson plots of grain boundary perimeter against magnification. Grain boundaries were revealed using conventional metallographic techniques and measurements were taken with the aid of an automatic image analizer (Quantimet 520) attached to an optical microscope. The magnifications used were 50, 100, 200, 400, and 1000X. The samples were obtained from a 4” diameter tubing, machined according to ASTM A370 standard test method and deformed to 5, 10, 15, and 20 % tensile strain. The results show that the fractal dimension of the grain boundaries changes as deformation is imparted to the material.These results suggest that fractal dimension may be used to describe microstructural evolution of metals during deformation processes.

scholarly journals COMPARISON TENSILE STRENGTH OF NATURAL AND SYNTHETIC ABSORBABLE SUTURES

2019 ◽  
pp. 157-159
Author(s):  
TJOKORDA GDE TIRTA NINDHIA ◽  
PUTU ASTAWA ◽  
TJOKORDA SARI NINDHIA ◽  
WAYAN SURATA I
Keyword(s):  
Tensile Strength ◽  
Optical Microscope ◽  
Standard Test ◽  
Chromic Catgut ◽  
Test Method ◽  
Natural Material ◽  
Synthetic Material ◽  
Absorbable Sutures ◽  
Surface Irregularities ◽  
Natural And Synthetic

Objective: The aim of the investigation is to evaluate and to compare the tensile strength of commercial natural and synthetic absorbable suturematerials currently used in surgery. The natural absorbable sutures of chromic catgut are prepared for this purpose as well as commercial syntheticabsorbable sutures made from polyglycolide.Methods: The analysis has been carried out following the standard test method for tensile strength and Young’s modulus of fiber ASTM C1557-03.Measuring the diameter of each suture has been carried out with an optical microscope to determine the accuracy of manufacturers’ data. Tensiletesting has been performed to evaluate the tensile strength of each type of sutures. The modulus elasticity and strain (ϵ) obtained are also presented.Results: The results show that sutures made from braided synthetic material of polyglycolide (violet coated) present a tensile strength remarkablysuperior (1070.292 MPa) to that of natural absorbable sutures of chromic catgut (392.276 MPa). Using optical macro microscope analysis,monofilament sutures present less surface irregularities than multifilament polyglycolide sutures. Chromic catgut monofilament sutures present lesssurface irregularities than multifilament polyglycolide.Conclusion: Tensile test of absorbable sutures was conducted in this research. Two types of absorbable sutures were investigated and compared. It isfound that sutures made from braided synthetic material of polyglycolide (violet coated) having much better tensile strength comparing with suturesmade from natural material (chromic catgut monofilament).

Effect of Frequency and Boost on the Breakdown of XLPE Cable with Inserted Needle Defects

2014 ◽  
Vol 986-987 ◽  
pp. 1817-1820
Author(s):  
Wei Wei Li ◽  
Qiang Shi
Keyword(s):  
Fractal Dimension ◽  
Breakdown Voltage ◽  
Power Transmission ◽  
Electrical Power ◽  
Fractal Dimensions ◽  
Optical Microscope ◽  
Test Method ◽  
Step Test ◽  
Xlpe Cable ◽  
Box Counting Method

Cross-linked polyethylene cables are widely used in power transmission system. In this work the effect of frequency and boost on the breakdown performance of XLPE cable with inserted needle defects was investigated by the frequency-tund resonant system with frequency ranging from 20Hz to 300Hz. The breakdown paths were observed by an optical microscope, and the fractal dimensions of the paths were estimated according to box-counting method. It was found that, with the increase of frequency, the variation of path fractal dimension as a function of frequency corresponded to that of breakdown voltage. Compared with the continuous boost method, the frequency, at which the fractal dimension of breakdown paths approached saturation and the breakdown voltage peaked, became lower under step test method. The increase of breakdown voltage is due to the increase of electrical power used for the initiation and development of dense discharge paths.

scholarly journals Microstructure, Strength, and Fracture Topography Relations in AISI 316L Stainless Steel, as Seen through a Fractal Approach and the Hall-Petch Law

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Oswaldo Antonio Hilders ◽  
Naddord Zambrano ◽  
Ramón Caballero
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Fractal Dimension ◽  
Fracture Surface ◽  
Surface Irregularity ◽  
Aisi 316L ◽  
Fractal Approach ◽  
Fracture Surface Roughness ◽  
Fracture Topography ◽  
316L Steel

The influence of the fracture surface fractal dimension DF and the fractal dimension of grain microstructure DM on the strength of AISI 316L type austenitic stainless steel through the Hall-Petch relation has been studied. The change in complexity experimented by the net of grains, as measured by DM, is translated into the respective fracture surface irregularity through DF, in such a way that the higher the grain size (lower DM values) the lower the fracture surface roughness (lower values of DF) and the shallower the dimples on the fractured surfaces. The material was heat-treated at 904, 1010, 1095, and 1194°C, in order to develop equiaxed grain microstructures and then fractured by tension at room temperature. The fracture surfaces were analyzed with a scanning electron microscope, DF was determined using the slit-island method, and the values of DM were taken from the literature. The relation between grain size, DM, mechanical properties, and DF, developed for AISI 316L steel, could be generalized and therefore applied to most of the common micrograined metal alloys currently used in many key engineering areas.

scholarly journals ON INVESTIGATION OF TENSILE STRENGTH OF COMMERCIAL SYNTHETIC NON-ABSORBABLE SUTURE MADE FROM OF BLUE POLYPROPYLENE MONOFILAMENT

2021 ◽  
pp. 75-78
Author(s):  
TJOKORDA GDE TIRTA NINDHIA ◽  
I PUTU ASTAWA ◽  
TJOKORDA SARI NINDHIA ◽  
I WAYAN SURATA
Keyword(s):  
Tensile Strength ◽  
Modulus Of Elasticity ◽  
Optical Microscope ◽  
Standard Test ◽  
Test Method ◽  
Absorbable Suture ◽  
Average Strain ◽  
Plastic Properties ◽  
Average Tensile Strength ◽  
Polypropylene Monofilament

Objective: The purpose of this research is to investigate the tensile strength of commercial synthetic non-absorbable suture made from blue polypropylene monofilament that commonly used in surgery.Methods: The commercial synthetic non-absorbable made from blue polypropylene monofilament was prepared for this purpose. The ASTM C1557-03 was used as a standard the method for analysis. For accuracy of the measurement, the diameter of the sutures was measured using optical microscope. The tensile strength, strain at failure, and modulus elasticity of the sutures were measured following instruction from the standard test method. The graph strain versus stress was provided.Results: Results show that that the average tensile strength of five valid tested samples is about 875.812 MPa. The average strain is found about 0.282. The average of modulus of elasticity is 4026.069 MPa.Conclusion: It is concluded that the sutures of commercial synthetic non-absorbable suture made from blue polypropylene monofilament having linier elastic as well as plastic properties. The average tensile strength of five valid tested samples is about 875.812 MPa. The average strain at failure is found about 0.282. The average of modulus of elasticity is 4026.069 MPa.

Improvement of the Long-Term Reliability of Interconnection by Controlling the Crystallinity of Grain Boundaries

2015 ◽  
Author(s):  
Takahiro Nakanishi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Ion Beam ◽  
Diffusion Constant ◽  
Diffraction Method ◽  
Electron Back Scatter Diffraction ◽  
Test Method ◽  
Electroplated Copper

Electroplated copper thin films have started to be employed as the interconnection material in TSV structures of 3D semiconductor modules because of its low electric resistivity and high thermal conductivity. However, electrical and mechanical properties of electroplated copper thin-films have been found to vary drastically depending on their microtexture. In particular, the crystallographic quality (crystallinity) of grain boundaries in the electroplated copper thin-films plays an important role on the variations of these properties and the long-term reliability of the interconnections. This is because grain boundaries are the area where the atomic alignment of mateerials is disordered and thus, various defects such as vacancies, dislocations, impurities, and strain easily concentrate around them. This disorder of the atomic alignment causes the increase in the electrical resistivity, diffusion constant along the grain boundaries, and the brittleness of the material. Therefore, it is very important to evaluate the characteristics of a grain boundary quantitatively in order to control and assure the properties of the electroplated copper thin films. In this study, a novel tensile test method that can measure the strength of a grain boundary has been developed by using a focused ion beam system. In order to investigate the effect of the crystallinity of grain boundaries on their strength, an electron back-scatter diffraction method (EBSD) was employed for the quantitative characterization of grain boundaries. It was confirmed that the strength of grain boundaries with low crystallinity was much lower than that with high crystallinity.

scholarly journals Interfacial Reactions between AlSi10 Foam Core and AISI 316L Steel Sheets Manufactured by In-Situ Bonding Process

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1374
Author(s):  
Girolamo Costanza ◽  
Maria Elisa Tata
Keyword(s):  
Cold Water ◽  
Optical Microscope ◽  
Bonding Process ◽  
Process Conditions ◽  
Equivalent Diameter ◽  
Al Alloy ◽  
Aisi 316L ◽  
Hydrogen Bubbles ◽  
316L Steel

Aluminum foam sandwiches (AFS) with AlSi10 foam cores and AISI 316L steel skins are manufactured by an in-situ bonding process. The precursor of the core foam was made with the powder compacted method. The precursor and skins, coupled together, were then heated up to the melting point of the Al alloy. The gas released by the blowing agent formed hydrogen bubbles in the melt. producing the foam. Such a porous structure was kept frozen at room temperature via cooling in cold water. To optimize the process conditions, some foaming experiments have been conducted with different holding times and temperatures. Such manufactured AFS were cut, chemically etched and studied with an optical microscope associated with image analysis software to get information about pores morphology in terms of circularity and equivalent diameter. The interface AlSi10-AISI316L has been characterized by SEM and EDX to investigate the bonding conditions between cores and skins. Finally, the AFS have been polished and etched to analyze the microstructure. Quasi-static compressive tests have been performed on the AFS. Obtained results showed that the interface formed during the foaming can be characterized by the inter-diffusion of alloying elements, as confirmed by the good quality of metallurgical joints.

Measurement of the Displacement Across a Coincidence Grain Boundary

1977 ◽  
Vol 35 ◽  
pp. 124-125
Author(s):  
J. W. Matthews ◽  
W. M. Stobbs
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Stacking Fault ◽  
The Other ◽  
Measuring Technique ◽  
High Angle ◽  
Twin Boundaries ◽  
Rigid Displacement ◽  
Cubic Crystals ◽  
Lattice Displacement

Many high-angle grain boundaries in cubic crystals are thought to be either coincidence boundaries (1) or coincidence boundaries to which grain boundary dislocations have been added (1,2). Calculations of the arrangement of atoms inside coincidence boundaries suggest that the coincidence lattice will usually not be continuous across a coincidence boundary (3). There will usually be a rigid displacement of the lattice on one side of the boundary relative to that on the other. This displacement gives rise to a stacking fault in the coincidence lattice.Recently, Pond (4) and Smith (5) have measured the lattice displacement at coincidence boundaries in aluminum. We have developed (6) an alternative to the measuring technique used by them, and have used it to find two of the three components of the displacement at {112} lateral twin boundaries in gold. This paper describes our method and presents a brief account of the results we have obtained.

Observations of dislocation interactions with recrystallized grain boundaries

1988 ◽  
Vol 46 ◽  
pp. 628-629
Author(s):  
C. W. Price
Keyword(s):  
Dislocation Density ◽  
Grain Boundary ◽  
Strain Rate ◽  
Grain Boundaries ◽  
Dislocation Structure ◽  
Hot Deformation ◽  
Static Recrystallization ◽  
High Dislocation Density ◽  
High Angle ◽  
Dislocation Interactions

Little evidence exists on the interaction of individual dislocations with recrystallized grain boundaries, primarily because of the severely overlapping contrast of the high dislocation density usually present during recrystallization. Interesting evidence of such interaction, Fig. 1, was discovered during examination of some old work on the hot deformation of Al-4.64 Cu. The specimen was deformed in a programmable thermomechanical instrument at 527 C and a strain rate of 25 cm/cm/s to a strain of 0.7. Static recrystallization occurred during a post anneal of 23 s also at 527 C. The figure shows evidence of dissociation of a subboundary at an intersection with a recrystallized high-angle grain boundary. At least one set of dislocations appears to be out of contrast in Fig. 1, and a grainboundary precipitate also is visible. Unfortunately, only subgrain sizes were of interest at the time the micrograph was recorded, and no attempt was made to analyze the dislocation structure.

Measurement of solute segregation to grain boundaries in the AEM: A review

1988 ◽  
Vol 46 ◽  
pp. 606-607
Author(s):  
D. B. Williams ◽  
A. D. Romig
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Boundary Misorientation ◽  
Collector Plate ◽  
Segregation Process ◽  
Grain Boundary Misorientation ◽  
Structure Boundary ◽  
Equilibrium Segregation

The segregation of solute or imparity elements to grain boundaries can occur by three well-defined processes. The first is Gibbsian segregation in which an element of minimal matrix solubility confines itself to a monolayer at the grain boundary. Classical examples include Bi in Cu and S or P in Fe. The second process involves the depletion of excess matrix solute by volume diffusion to the boundary. In the boundary, the solute atoms diffuse rapidly to precipitates, causing them to grow by the ‘collector-plate mechanism.’ Such grain boundary diffusion is thought to initiate “Diffusion-Induced Grain Boundary Migration,” (DIGM). This process has been proposed as the origin of eutectoid transformations or discontinuous grain boundary reactions. The third segregation process is non-equilibrium segregation which result in a solute build-up around the boundary because of solute-vacancy interactions.All of these segregation phenomena usually occur on a sub-micron scale and are often affected by the nature of the grain boundary (misorientation, defect structure, boundary plane).

Grain boundary segregation in metals

1992 ◽  
Vol 50 (2) ◽  
pp. 1204-1205
Author(s):  
C.L. Briant
Keyword(s):  
Fracture Surface ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Material Properties ◽  
Electron Spectroscopy ◽  
High Vacuum ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Local Concentration ◽  
The One

Grain boundary segregation is the process by which solute elements in a material diffuse to the grain boundaries, become trapped there, and increase their local concentration at the boundary over that in the bulk. As a result of this process this local concentration of the segregant at the grain boundary can be many orders of magnitude greater than the bulk concentration of the segregant. The importance of this problem lies in the fact that grain boundary segregation can affect many material properties such as fracture, corrosion, and grain growth.One of the best ways to study grain boundary segregation is with Auger electron spectroscopy. This spectroscopy is an extremely surface sensitive technique. When it is used to study grain boundary segregation the sample must first be fractured intergranularly in the high vacuum spectrometer. This fracture surface is then the one that is analyzed. The development of scanning Auger spectrometers have allowed researchers to first image the fracture surface that is created and then to perform analyses on individual grain boundaries.

Sign in / Sign up

Export Citation Format

Share Document