scholarly journals On the Stress Dependence of Subgrain Size

1982 ◽  
Vol 5 (3) ◽  
pp. 127-152 ◽  
Author(s):  
G. H. Edward ◽  
M. A. Etheridge ◽  
B. E. Hobbs
Keyword(s):  
Material Properties ◽  
Subgrain Size ◽  
Dynamic Balance ◽  
Dislocation Generation ◽  
Proportionality Constant ◽  
Creep Stress ◽  
Dislocation Annihilation ◽  
Size Relation ◽  
Induced Dislocation ◽  
Environmental Dependence

A simple model of the dynamic balance between deformation induced dislocation generation and climb controlled dislocation annihilation in subgrain walls is outlined. This results in a stress-subgrain size relationship which involves various material properties, including the creep stress exponent and the creep diffusivity.Assuming a fixed slip distance for mobile dislocations, the theory predicts that the subgrain size (d) depends on the stress (σ) as d4∝σ−n, where n is the creep exponent, and the proportionality constant is dependent on material properties, temperature, and other environmental variables. This theoretical prediction is satisfactorily compared with published experimental results for a variety of materials.The implications of the environmental dependence of the stress-subgrain size relation with regard to its use as a palaeopiezometer in naturally deformed minerals are discussed.

Oxide Precipitate‐Induced Dislocation Generation in Heavily Boron‐Doped Czochralski Silicon

1999 ◽  
Vol 146 (9) ◽  
pp. 3461-3465 ◽  
Author(s):  
T. Ono ◽  
A. Romanowski ◽  
E. Asayama ◽  
H. Horie ◽  
K. Sueoka ◽  
...  
Keyword(s):  
Dislocation Generation ◽  
Czochralski Silicon ◽  
Boron Doped ◽  
Induced Dislocation ◽  
Oxide Precipitate

Viscoelastic Material Properties of SU-8 and Carbon-Nanotube-Reinforced SU-8 Materials

2006 ◽  
Author(s):  
Seungbae Park ◽  
Soonwan Chung ◽  
Harold Ackler ◽  
Sandeep Makhar
Keyword(s):  
Carbon Nanotube ◽  
Strain Rate ◽  
Viscoelastic Material ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Mechanical Reliability ◽  
Creep Stress ◽  
Post Exposure Bake ◽  
Carbon Nano Tube ◽  
Composite Carbon

The viscoelastic material properties of SU-8 and carbon nanotube-reinforced SU-8 composite material are characterized by tensile testing. Dogbone samples of 0.1mm thickness are prepared by micro-fabrication process, which is composed of spin coat, soft bake, expose, and post exposure bake. To fabricate CNT polymer composite, carbon nano-tube of 0.2wt% is mixed with SU-8. To observe the effect of applied strain rate and temperature on Young's modulus and Poisson's ratio, strain rate is varied from 5×10-5 to 2.5×10-4 (/sec) at elevated temperatures in the range of 25 to 200°C. Since the viscoelastic material properties are important in polymer, creep, stress relaxation and dynamic mechanical analyses are performed at elevated temperatures. The viscoelastic material properties of SU-8 and CNT-reinforced SU-8 composite are compared, and the mechanical reliability of these polymers in MEMS applications is discussed.

Impact of Silicon Wafer Material on Dislocation Generation in Local Oxidation

1998 ◽  
Vol 532 ◽  
Author(s):  
I. V. Peidous ◽  
R. Sundaresan ◽  
E. Quek ◽  
Y. K. Leung ◽  
M. Beh
Keyword(s):  
Surface Defect ◽  
Depth Distribution ◽  
Defect Density ◽  
Dislocation Generation ◽  
Local Oxidation ◽  
Dislocation Movement ◽  
Defect Nucleation ◽  
Critical Resolved Shear Stress ◽  
Induced Dislocation

ABSTRACTCrystalline quality of locally oxidized silicon wafers has been studied. Wafers from different supply sources were found to be differently susceptible to stress-induced dislocation generation, although they had been produced to the same specification. On the basis of the analysis of a depth distribution of the dislocations, critical resolved shear stress of dislocation movement in the bulk areas of the wafers was determined. It varied from about 1.65 to 5.12 MPa and correlated positively to the surface defect density. The results show that uncontrollable variations of bulk silicon properties may significantly influence the stress-induced defect nucleation on the surface of wafers during processing.

Comparison of in situ and in vitro studies of pericardial pressure-volume relation in dogs

1986 ◽  
Vol 251 (2) ◽  
pp. H421-H427 ◽  
Author(s):  
G. L. Freeman ◽  
W. C. Little
Keyword(s):  
Material Properties ◽  
Nonlinear Regression Analysis ◽  
Stress Strain ◽  
Testing Conditions ◽  
Proportionality Constant ◽  
Stress Strain Relation ◽  
Pericardial Pressure ◽  
Volume Relation

Whether the material properties of the pericardial membrane are the key determinants of the in situ pericardial pressure-volume relation is not known. Although both the pressure-volume relation of the intact pericardium and the stress-strain relation of isolated pericardial samples are nonlinear, it is not clear how closely these phenomena are related. To directly examine this question we compared the pressure-volume, pressure-normalized volume, and stress-strain relations of pericardia from six dogs tested both in situ and in vitro. The curves generated under the two sets of conditions were different. The transition from the compliant to the noncompliant portion of the curve was more acute under in vitro conditions. Nonlinear regression analysis using a monoexponential function of the form Y = alpha (e beta chi-1) showed beta, the proportionality constant for the slope of the curve, to be larger for each form of analysis under in vitro testing conditions as follows: 0.002 +/- 0.009 vs. 0.078 +/- 0.029, P less than 0.002 for pressure-volume; 3.52 +/- 1.75 vs. 11.03 +/- 5.31, P less than 0.005 for pressure-normalized volume; and 19.6 +/- 6.6 vs. 62.3 +/- 18.8, P less than 0.001 for stress-strain. These differences in the pressure-volume relation of the intrapericardial space in situ and the isolated pericardium in vitro suggest that pericardial attachments present in situ may buffer the loading of the membrane itself. We conclude that the pressure-volume relation of the intrapericardial space is only partly determined by the properties of the isolated pericardium alone and is also influenced by other components of the intact pericardium.

A comparative study of thermal stress induced dislocation generation in pulled GaAs, InP, and Si crystals

1981 ◽  
Vol 52 (5) ◽  
pp. 3331-3336 ◽  
Author(s):  
A. S. Jordan ◽  
R. Caruso ◽  
A. R. VonNeida ◽  
J. W. Nielsen
Keyword(s):  
Thermal Stress ◽  
Comparative Study ◽  
Dislocation Generation ◽  
Induced Dislocation

Local oxidation induced dislocation generation near [100] Si3N4film edges

1983 ◽  
Vol 43 (12) ◽  
pp. 1120-1122 ◽  
Author(s):  
J. Vanhellemont ◽  
J. Van Landuyt ◽  
S. Amelinckx ◽  
C. Claeys ◽  
G. Declerck ◽  
...  
Keyword(s):  
Dislocation Generation ◽  
Local Oxidation ◽  
Induced Dislocation
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