Ab initiocalculation of the ideal tensile and shear strength of cubic silicon nitride

2003 ◽  
Vol 67 (3) ◽  
Author(s):  
Cenk Kocer ◽  
Naoto Hirosaki ◽  
Shigenobu Ogata
Keyword(s):  
Shear Strength ◽  
Silicon Nitride ◽  
The Ideal

Anab initiocalculation of the ideal tensile strength of β-silicon nitride

2001 ◽  
Vol 64 (17) ◽  
Author(s):  
Shigenobu Ogata ◽  
Naoto Hirosaki ◽  
Cenk Kocer ◽  
Hiroshi Kitagawa
Keyword(s):  
Tensile Strength ◽  
Silicon Nitride ◽  
The Ideal

The Temperature-Dependent Ideal Shear Strength of Solid Single Crystals

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Tianbao Cheng ◽  
Daining Fang ◽  
Yazheng Yang
Keyword(s):  
Shear Strength ◽  
Theoretical Model ◽  
Melting Point ◽  
Single Crystals ◽  
Elevated Temperatures ◽  
Absolute Zero ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
First Time ◽  
The Ideal

Knowledge of the ideal shear strength of solid single crystals is of fundamental importance. However, it is very hard to determine this quantity at finite temperatures. In this work, a theoretical model for the temperature-dependent ideal shear strength of solid single crystals is established in the view of energy. To test the drawn model, the ideal shear properties of Al, Cu, and Ni single crystals are calculated and compared with that existing in the literature. The study shows that the ideal shear strength first remains approximately constant and then decreases almost linearly as temperature changes from absolute zero to melting point. As an example of application, the “brittleness parameter” of solids at elevated temperatures is quantitatively characterized for the first time.

Comparison of Solutions of Stress Field Based on Hertzian and Combined Numerical-Crystallographic Approaches Beneath Nanoindenter

2011 ◽  
Vol 488-489 ◽  
pp. 395-398 ◽  
Author(s):  
Jana Horníková ◽  
Pavel Šandera ◽  
Jaroslav Pokluda
Keyword(s):  
Shear Strength ◽  
Stress Field ◽  
Nanoindentation Test ◽  
Displacement Curve ◽  
Dislocation Generation ◽  
Metallic Substrates ◽  
Shear Component ◽  
Local Shear ◽  
Close Distance ◽  
The Ideal

Nanoindentation is considered to be a very promising experimental approach to measuring the ideal shear strength since the stressed volume beneath the sharp indenter may be defect-free. The local shear component of the stress reaches its maximum value at some close distance from the indenter in the bulk. The value of the stress can reach the ideal shear strength and, consequently become high enough to nucleate dislocations. This process might be detected as a pop-in on the nanoindentation load-displacement curve. To model the nanoindentation test for that purpose, three different approaches have been used in this works. The first approach is based on the analytical Hertzian solution of the stress field beneath the nanoindenter where only a continuum mechanics is taken into account. The second concept is based on the numerical solution without crystallographic considerations and the third one respects the fact that the dislocation generation in the substrate is subjected to crystallographic rules. The aim of this article is to compare all these concepts by their application to the nanoindentation process performed on selected bcc and fcc metallic substrates.

The mechanical properties of perfect crystals I. The ideal strength

1972 ◽  
Vol 330 (1582) ◽  
pp. 291-308 ◽  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Strength ◽  
Sodium Chloride ◽  
Room Temperature ◽  
Cleavage Plane ◽  
Ideal Strength ◽  
Lennard Jones ◽  
Computer Calculations ◽  
The Ideal

In this paper we present computer calculations of the ideal strength of crystals of sodium chloride and argon, for a variety of modes of homogeneous deformation. As models of the interatomic binding we employ the simple, two-body, central-force Born-Mayer and Lennard-Jones potentials respectively. The calculations for argon are appropriate to absolute zero, those for sodium chloride to room temperature. The results indicate a very marked anisotropy of the ideal tensile strength for sodium chloride, with a pronounced minimum at <100>, which is consistent with the observed cleavage on this plane. The ideal tensile strength of argon is shown to be much less dependent on orientation, which accords with the lack of any obvious cleavage plane in this material. We also make some estimates of the ideal shear strength, and find this to be a minimum for {111} <112> shear for both argon and sodium chloride.

First-Principles Calculations of Grain Boundary-Surface for Various Grain Boundaries with Different Energies in Aluminum

2007 ◽  
Vol 551-552 ◽  
pp. 331-336 ◽  
Author(s):  
Tokuteru Uesugi ◽  
Y. Inoue ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Shear Strength ◽  
Grain Boundary ◽  
First Principles ◽  
Boundary Surface ◽  
Grain Boundary Sliding ◽  
Excess Energy ◽  
First Principles Calculations ◽  
Perfect Single Crystal ◽  
Boundary Sliding ◽  
The Ideal

The grain boundary surface is the excess energy of the grain boundary as the lattice on one side of the grain is translated relative to the lattice on the other side of the grain. The maximum in the slope of the grain boundary surface determines the ideal shear strength for the grain boundary sliding. We presented the ideal shear strength for the grain boundary sliding in aluminum Σ3(11 2)[110] tilt grain boundary from the first-principles calculations. The ideal shear strength for the grain boundary sliding was much smaller than the ideal shear strength of a perfect single crystal.

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