Use of Indentation Fracture to Determine Fracture Toughness

2009 ◽  
pp. 103-103-9 ◽  
Author(s):  
RH Marion
Keyword(s):  
Fracture Toughness ◽  
Indentation Fracture ◽  
Determine Fracture Toughness

scholarly journals VERIFICATION OF BEHAVIOUR OF HUMAN ENAMEL FOR FRACTURE TOUGHNESS DETERMINATION

2018 ◽  
Vol 58 (4) ◽  
pp. 226 ◽  
Author(s):  
Petra Hájková ◽  
Aleš Jíra ◽  
Luboš Řehounek
Keyword(s):  
Fracture Toughness ◽  
Loading Rate ◽  
Fracture Behaviour ◽  
Fracture Initiation ◽  
Fracture Test ◽  
Indentation Fracture ◽  
Human Enamel ◽  
Reduced Modulus ◽  
The Impact ◽  
Determine Fracture Toughness

<p>Enamel is the hardest biological tissue in the human body because of its structure<br />and composition. The structure of interlocking rods enables this biomaterial to resist the stresses of mastication. Unfortunately, enamel is prone to fracture initiation and growth. Determining fracture toughness of enamel is a difficult task. The lack of thickness makes it impossible to prepare samples which could be analyzed by usual methods. Other authors use Vickers indentation fracture test (VIF) to determine fracture toughness of enamel ordinarily. VIF is, however, not generally acceptable.<br />The aim of this study is verification of fracture behaviour of enamel using nanoindentation. In the study the impact of changes of hardness (HIT) and reduced modulus (Er) caused by crack initiation and growth on fracture toughness determination is observed. The next goal is evaluation of loading rate impact.</p>

A Transparent and Tough β-Si3N4 Ceramic with a Whiskery Microstructure

2015 ◽  
Vol 655 ◽  
pp. 1-5
Author(s):  
Peng Xi Li ◽  
Hong Qiang Wang ◽  
Liu Cheng Gui ◽  
Jun Li ◽  
Hai Long Zhang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Amorphous Phase ◽  
Hot Pressing ◽  
High Density ◽  
Indentation Fracture ◽  
Indentation Fracture Toughness ◽  
Resultant Material

The transparent β-Si3N4ceramic with a whisker-like microstructure was prepared by hot-pressing at 2000 °C for 26 h, with MgSiN2as an additive. The resultant material achieves the maximum transmittance of 70 % at the wavelength of about 2.5 μm and the transmittance value keeps higher than 60 % in the range of 700-4500 nm wavelength, which is attributed to the very small amount of the intergranular amorphous phase along with high density. The present transparent β-Si3N4ceramic exhibits an indentation fracture toughness of 7.2±0.3 MPa m1/2.

Pulsed Electric Current Sintered Cr2O3-rGO Composites

2016 ◽  
Vol 721 ◽  
pp. 419-424
Author(s):  
M. Erkin Cura ◽  
Vivek Kumar Singh ◽  
Panu Viitaharju ◽  
Joonas Lehtonen ◽  
Simo Pekka Hannula
Keyword(s):  
Fracture Toughness ◽  
Graphene Oxide ◽  
Electric Current ◽  
Chromium Oxide ◽  
High Hardness ◽  
High Wear Resistance ◽  
Carbide Formation ◽  
Indentation Fracture ◽  
Pulsed Electric Current ◽  
Indentation Fracture Toughness

Chromium oxide is a promising material for applications where excellent corrosion resistance, high hardness, and high wear resistance are needed. However, its use is limited because of low fracture toughness. Improvement of fracture toughness of chromium oxide while maintaining its afore mentioned key properties is therefore of high interest. In this communication we study the possibility of increasing the toughness of pulsed electric current sintered (PECS) chromium oxide by the addition of graphene oxide (GO). The indentation fracture toughness was improved markedly with the addition of graphene oxide. Materials prepared by direct chemical homogenization had better fracture toughness. In composites with 10 vol.% GO piling of thin graphene oxide layers resulted in the formation of graphite layers between Cr2O3 and in carbide formation, which were observed to be the main reasons for the degradation of the mechanical properties. The distribution of graphene oxide was more homogeneous, when the GO amount was 0.1 vol.% and the formation of graphitic layers were avoided due to lesser amount of GO as well as ultrasonic treatment following the ball milling.

Structure and Properties of Single Crystal Al2O3 Implanted with Chromium and Zirconium

1981 ◽  
Vol 7 ◽  
Author(s):  
C. J. Mchargue ◽  
H. Naramoto ◽  
B. R. Appleton ◽  
C. W. White ◽  
J. M. Williams
Keyword(s):  
Fracture Toughness ◽  
Single Crystal ◽  
Single Crystals ◽  
Solid Solutions ◽  
Rutherford Backscattering ◽  
Structure And Properties ◽  
Indentation Fracture ◽  
Surface Layers ◽  
Indentation Fracture Toughness

ABSTRACTSingle crystals of Al2O3 were implanted with chromium and zirconium to fluences of 1 × 1016 to 1 × 1017 ions cm−2. Rutherford backscattering-channeling studies showed the surface layers to be damaged but crystalline with the implanted ions randomly distributed. The microhardness and indentation fracture toughness were higher for the random solutions than for conventionally formed solid solutions. Changes in structure and properties caused by annealing in air at temperatures up to 1800°C were studied.

Indentation Fracture of Macro-Defect-Free (MDF) Cements

1989 ◽  
Vol 179 ◽  
Author(s):  
Yeong-Shyung Chou ◽  
J. J. Mecholsky ◽  
M. R. Silsbee ◽  
D. M Roy ◽  
J. H. Adair ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Surface ◽  
Surface Analysis ◽  
Polymer Content ◽  
Indentation Fracture ◽  
Fracture Surface Analysis ◽  
Mdf Cements ◽  
Good Agreement

AbstractThe fracture toughness of MDF (macro-defect-free) cement with different polymer contents has been investigated by the indentation-strength method and fracture surface analysis. It was found that the fracture toughness obtained by these two different techniques showed good agreement for the low (3 wt.%) polymer cement. The ultimate (apparent) toughnesses are 1.3 Mpam1/2 for low polymer content and 2.2 Mpam1/2 for high (8 wt.%) polymer content cement. Different microcracking and sponge-like microstructures have been observed and discussed.

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