Rayleigh instabilities in crystalline solids: Evolution of finite-aspect-ratio pore channels in sapphire

2008 ◽  
Vol 56 (9) ◽  
pp. 1967-1980 ◽  
Author(s):  
Melissa K. Santala ◽  
Andreas M. Glaeser
Keyword(s):  
Aspect Ratio ◽  
Crystalline Solids ◽  
Rayleigh Instabilities

Contrast From Point Defects in The Infinitesimal Approximation

1980 ◽  
Vol 38 ◽  
pp. 350-351
Author(s):  
L. J. Sykes ◽  
J. J. Hren
Keyword(s):  
Electron Microscope ◽  
Point Defects ◽  
Broad Class ◽  
Stacking Fault ◽  
Crystalline Solids ◽  
Dislocation Loops ◽  
Analytical Expression ◽  
Stacking Fault Tetrahedra

In electron microscope studies of crystalline solids there is a broad class of very small objects which are imaged primarily by strain contrast. Typical examples include: dislocation loops, precipitates, stacking fault tetrahedra and voids. Such objects are very difficult to identify and measure because of the sensitivity of their image to a host of variables and a similarity in their images. A number of attempts have been made to publish contrast rules to help the microscopist sort out certain subclasses of such defects. For example, Ashby and Brown (1963) described semi-quantitative rules to understand small precipitates. Eyre et al. (1979) published a catalog of images for BCC dislocation loops. Katerbau (1976) described an analytical expression to help understand contrast from small defects. There are other publications as well.

Modification of MnS inclusion by tellurium in 38MnVS6 micro-alloyed steel

2020 ◽  
Vol 117 (6) ◽  
pp. 615
Author(s):  
Ping Shen ◽  
Lei Zhou ◽  
Qiankun Yang ◽  
Zhiqi Zeng ◽  
Kenan Ai ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Aspect Ratio ◽  
Strong Influence ◽  
Experimental Results ◽  
Alloyed Steel ◽  
Equivalent Diameter ◽  
Small Aspect Ratio ◽  
Steel Quality ◽  
Eds Analysis ◽  
Micro Alloyed Steel

In 38MnVS6 steel, the morphology of sulfide inclusion has a strong influence on the fatigue life and machinability of the steel. In most cases, the MnS inclusions show strip morphology after rolling, which significantly affects the steel quality. Usually, the MnS inclusion with a spherical morphology is the best morphology for the steel quality. In the present work, tellurium was applied to 38MnVS6 micro-alloyed steel to control the MnS inclusion. Trace tellurium was added into 38MnVS6 steel and the effect of Te on the morphology, composition, size and distribution of MnS inclusions were investigated. Experimental results show that with the increase of Te content, the equivalent diameter and the aspect ratio of inclusion decrease strikingly, and the number of inclusions with small aspect ratio increases. The inclusions are dissociated and spherized. The SEM-EDS analysis indicates that the trace Te mainly dissolves in MnS inclusion. Once the MnS is saturated with Te, MnTe starts to generate and wraps MnS. The critical Te/S value for the formation of MnTe in the 38MnV6 steel is determined to be approximately 0.075. With the increase of Te/S ratio, the aspect ratio of MnS inclusion decreases and gradually reaches a constant level. The Te/S value in the 38MnVS6 steel corresponding to the change of aspect ratio from decreasing to constant ranges from 0.096 to 0.255. This is most likely to be caused by the saturation of Te in the MnS inclusion. After adding Te in the steel, rod-like MnS inclusion is modified to small inclusion and the smaller the MnS inclusion, the lower the aspect ratio.

PENINGKATAN KEMAMPUAN GURU BAHASA INDONESIA DALAM MENYUSUN RENCANA PROGRAM PEMBELAJARAN (RPP) SDN 015 PAGARAN TAPAH DARUSSALAM MELALUI METODE PEMBERIAN TUGAS

2017 ◽  
Vol 5 (3) ◽  
pp. 713
Author(s):  
Mukhlis '
Keyword(s):  
Aspect Ratio ◽  
Duty Cycle ◽  
Lesson Plans ◽  
Learning Program ◽  
School Subjects ◽  
Bahasa Indonesia

Based on the observation of some teachers found the symptoms as follows: the lack of abilityof Indonesian teachers in designing learning program (RPP), the learning device is only usedas a supplement and not to the needs of teaching, most teachers again if asked the lessonanswered not have or has not been made. The purpose of this research is to improve theability of Indonesian teachers in designing learning program (RPP) at SDN 015 PagaranTapah Darussalam through the method of administration tasks. This type of research is actionresearch school. Subjects in this study were teachers Indonesian as many as 12 people. Basedon the analysis and discussion can be concluded that the method of administration tasks canimprove the ability of Indonesian teachers in making learning device in SDN 015 PagaranTapah Darussalam through the method of administration tasks. Under these conditions, thelevel of acceptance of teachers increased. The aspect ratio capability Indonesian teachers inpreparing lesson plans through the provision of duty cycle I and II of the increase from 56%and the second cycle to 79%.

Development of an Ion Beam Probe System for Potential Measurement in the Low Aspect-Ratio Torus Experiment Device

2012 ◽  
Vol 132 (7) ◽  
pp. 567-573
Author(s):  
Hitoshi Tanaka ◽  
Shota Omi ◽  
Jun Katsuma ◽  
Yurie Yamamoto ◽  
Masaki Uchida ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Ion Beam ◽  
Potential Measurement ◽  
Low Aspect Ratio ◽  
Probe System ◽  
Experiment Device

Cosserat Modeling of Size Effects in Crystalline Solids

2000 ◽  
Vol 653 ◽  
Author(s):  
Samuel Forest
Keyword(s):  
Stress State ◽  
Size Effects ◽  
Elastic Inclusion ◽  
Characteristic Size ◽  
Infinite Matrix ◽  
Crystalline Solids ◽  
Generalized Continua ◽  
Absolute Size ◽  
Kink Bands ◽  
The Matrix

AbstractThe mechanics of generalized continua provides an efficient way of introducing intrinsic length scales into continuum models of materials. A Cosserat framework is presented here to descrine the mechanical behavior of crystalline solids. The first application deals with the problem of the stress field at a crak tip in Cosserat single crystals. It is shown that the strain localization patterns developping at the crack tip differ from the classical picture : the Cosserat continuum acts as a bifurcation mode selector, whereby kink bands arising in the classical framework disappear in generalized single crystal plasticity. The problem of a Cosserat elastic inclusion embedded in an infinite matrix is then considered to show that the stress state inside the inclusion depends on its absolute size lc. Two saturation regimes are observed : when the size R of the inclusion is much larger than a characteristic size of the medium, the classical Eshelby solution is recovered. When R is much small than the inclusion, a much higher stress is reached (for an inclusion stiffer than the matrix) that does not depend on the size any more. There is a transition regime for which the stress state is not homogeneous inside the inclusion. Similar regimes are obtained in the study of grain size effects in polycrystalline aggregates of Cosserat grains.

Sign in / Sign up

Export Citation Format

Share Document