The Sensitivity of Dislocation Rosettes to the Shape of a Berkovich Indenter on LiF and MgO Crystals

2020 ◽  
Vol 62 (8) ◽  
pp. 1386-1393
Author(s):  
D. Grabco ◽  
K. Pyrtsac ◽  
O. Shikimaka
Keyword(s):  
Berkovich Indenter

scholarly journals Application of the nanoindentation method in assessing of properties of cement composites modified with silica-magnetite nanostructures

2018 ◽  
Vol 163 ◽  
pp. 02002 ◽  
Author(s):  
Elzbieta Horszczaruk ◽  
Roman Jedrzejewski ◽  
Jolanta Baranowska ◽  
Ewa Mijowska
Keyword(s):  
Mechanical Properties ◽  
Magnetite Nanoparticles ◽  
Positive Influence ◽  
Cement Matrix ◽  
Core Shell ◽  
Indentation Modulus ◽  
Cement Composites ◽  
Interfacial Zone ◽  
Berkovich Indenter ◽  
The Core

The results of investigation of the cement composites modified with 5% of silica-magnetite nanostructures of the core-shell type are presented in the paper. The nanoindentation method employing three-sided pyramidal Berkovich indenter was used in the research. The mechanical properties and microstructure of the modified cement composites were evaluated on the basis of the values of hardness and indentation modulus measured inside the cement matrix and in the aggregate-paste interfacial zone. The results were compared with those obtained for the reference composites without nanostructures. The positive influence of the presence of silica-magnetite nanoparticles on the tested properties was found out.

Study on Nanolithography Process of Polycrystalline Copper Using Molecular Dynamic Simulation

2007 ◽  
Vol 340-341 ◽  
pp. 961-966
Author(s):  
Chan Il Kim ◽  
Young Suk Kim ◽  
Sang Il Hyun ◽  
Seung Han Yang ◽  
Jun Young Park ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Molecular Dynamic Simulation ◽  
Molecular Dynamic ◽  
Dynamic Simulation ◽  
Diamond Like Carbon ◽  
Polycrystalline Copper ◽  
Berkovich Indenter ◽  
Contact Surfaces ◽  
Dynamics Simulations

Molecular dynamics simulations are performed to verify the effect of grain boundary on nanolithography process. The model with about two hundred thousand copper (Cu) atoms is composed of two different crystal orientations of which contact surfaces are (101) and (001) planes. The grain boundary is located on the center of model and has 45 degreeangle in xz-plane. The tool is made of diamond-like-carbon with the shape of Berkovich indenter. As the tool is indented and plowed on the surface, dislocations are generated. Moreover, during the plowing process, the steps as well as the typical pile-ups are formed in front of the tool. These defects propagate into the surface of the substrate. As the tool approaches to the grain boundary, the defects are seen to be accumulated near the grain boundary. The shape of the grain boundary is also significantly deformed after the tool passes it. We observed the forces exerted on the tool by the contact with substrate, so that the friction coefficients can be obtained to address the effect of the grain boundary on the friction characteristics.

DETERMINATION OF VISCOELASTIC PROPERTIES OF THE PERIODONTAL LIGAMENT USING NANOINDENTATION TESTING AND NUMERICAL MODELING

2016 ◽  
Vol 16 (06) ◽  
pp. 1650089 ◽  
Author(s):  
HUIXIANG HUANG ◽  
WENCHENG TANG ◽  
YU YANG ◽  
BIN WU ◽  
BIN YAN
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Periodontal Ligament ◽  
Alveolar Bone ◽  
Spherical Indenter ◽  
Berkovich Indenter ◽  
Zener Model ◽  
Nanoindentation Experiment ◽  
Creep Models ◽  
Good Agreement

Viscoelasticity of the periodontal ligament (PDL) plays an important role in load transmission between tooth and alveolar bone, as well as tooth movement. This paper provides a novel nanoindentation experiment in combination with a rheological model to characterize the viscoelastic mechanical properties of the PDL. Two creep models of the indentation experiments with a Berkovich and a spherical indenter based on Zener model were developed. The hardness and reduced modulus were determined by using the Berkovich indenter. The parameters were identified through curve fittings. The fitting results show that the creep models are both in good agreement with the experimental data. Meanwhile, the models were both validated by comparing the numerical curves for load–depth relationship in loading segment with the corresponding experimental data. It is found that the spherical indenter is more suitable for testing the viscoelastic mechanical properties of the PDL than Berkovich indenter. Hence, the nanoindentation experiment with spherical indenter was simulated to further evaluate the Zener model by finite element analysis. The good agreement between the simulated results and experimental data demonstrates that the Zener model is capable of describing the viscoelastic mechanical behavior of the PDL.

scholarly journals Modeling and Experiment of the Critical Depth of Cut at the Ductile–Brittle Transition for a 4H-SiC Single Crystal

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 382 ◽  
Author(s):  
Peng Chai ◽  
Shujuan Li ◽  
Yan Li
Keyword(s):  
Single Crystal ◽  
Lateral Displacement ◽  
Tangential Force ◽  
Test System ◽  
Depth Of Cut ◽  
Critical Depth ◽  
Berkovich Indenter ◽  
Nose Radius ◽  
Brittle Transition ◽  
Critical Depth Of Cut

In this paper, a theoretical model of the critical depth of cut of nanoscratching on a 4H-SiC single crystal with a Berkovich indenter is proposed, and a series of scratch tests in a nanomechanical test system was performed. Through nanoindentation experimentation on fused quartz, the Berkovich indenter nose radius was indirectly confirmed using least squares. The range of critical depths of cut at the ductile–brittle transition was obtained by SEM observation, and the size of cracks was amplified with increasing scratching depth. The theoretical result of the critical depth of cut at the ductile–brittle transition for a 4H-SiC single crystal is 91.7 nm, which is close to the first obvious pop-in point of the relation curve between tangential force and lateral displacement. Repeated experimental results show good consistency and good agreement with other references.

Molecular Dynamics Simulation of Nanoindentation on Folded Chain Crystal of Polyethylene

2005 ◽  
Vol 297-300 ◽  
pp. 2247-2252 ◽  
Author(s):  
Kisaragi Yashiro ◽  
Atsushi Furuta ◽  
Yoshihiro Tomita
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Loading Rate ◽  
Dynamics Simulation ◽  
Delayed Response ◽  
Berkovich Indenter ◽  
Orthorhombic Crystal ◽  
Constant Loading ◽  
Constant Loading Rate ◽  
The Ideal

Nanoindentation tests on a folded chain crystal of polyethylene are implemented with the molecular dynamics simulation. The orthorhombic crystal is made of the planar zig-zag chains and has the thickness of about 10nm. The ideal Berkovich indenter is plunged into upper surface of the crystal down to 2nm with the constant loading rate of 200m/s or 2000m/s. After the holding time of 1000fs at the maximum depth, the indenter is then pulled up with the same speed. The results are summarized as follows; a) The indentation of 2000m/s remains the residual depression while that of 200m/s recovers the hollow, b) No elastic component is found in the deformation under the both rate of 200m/s and 2000m/s, c) The crystal deforms statically under the indentation of 200m/s while that of 2000m/s shows delayed response.

scholarly journals Mechanical Properties of Evaporated Gold Films. Hard Substrate Effect Correction

2008 ◽  
Vol 1086 ◽  
Author(s):  
Ke Du ◽  
Xiaolu Pang ◽  
Chi Chen ◽  
Alex A. Volinsky
Keyword(s):  
Mechanical Properties ◽  
Indentation Depth ◽  
Gold Film ◽  
Gold Films ◽  
Substrate Effect ◽  
Berkovich Indenter ◽  
Film Hardness ◽  
Polycrystalline Gold ◽  
Area Variation ◽  
Hard Substrates

AbstractNanoindentation tests using the Berkovich indenter tip were performed on 50 and 200 nm thick polycrystalline gold films deposited on hard substrates. Gold film hardness increased with the indentation depth due to the influence of the substrate. A procedure based on the Joslin-Oliver method was introduced to correct for the substrate effect. The method utilizes the fact that the measured elastic modulus does not change significantly with the indentation depth, which allows reducing the contact area variation used in the hardness calculation.

A Method to Determine Fracture Toughness Using Berkovich Indenter for Bulk Materials

2013 ◽  
Vol 331 ◽  
pp. 456-460
Author(s):  
Min He ◽  
Duan Hu Shi ◽  
Feng Yang ◽  
Ning Zhang ◽  
Hua Feng Guo
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Penetration Depth ◽  
Effective Elastic Modulus ◽  
Berkovich Indenter ◽  
Bulk Materials ◽  
Ductile Materials ◽  
Penetration Depths ◽  
Determine Fracture Toughness

An indentation approach with Berkovich indenter is proposed to determine fracture toughness for ductile materials. With decrease of effective elastic modulus, an approximate linear relationship between logarithmic plastic penetration depth and logarithmic effective elastic modulus, and a quadratic polynomial relationship between the plastic penetration depths and penetration loads are exhibited by indentation investigation with Berkovich indenter. The damage constructive equation of effective elastic modulus is proposed to determine the critical effective elastic modulus at the fracture point, which is the key problem to calculate the indentation energy to fracture. The critical plastic penetration depth is identified after the critical effective elastic modulus can be predicted by conventional mechanical properties. The fracture toughness is calculated according to the equation of penetration load, plastic penetration depth and the critical plastic penetration depth.

Measurement of Sample Tilt by Residual Imprint Morphology of Berkovich Indenter

2018 ◽  
Vol 48 (4) ◽  
pp. 20180136 ◽  
Author(s):  
Chenghui Gao ◽  
Ligang Yao ◽  
Ming Liu
Keyword(s):  
Berkovich Indenter
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