Fracture Toughness of Alumina Ceramics Determined by Vickers Indentation Technique

2012 ◽  
Vol 54 (4) ◽  
pp. 228-232 ◽  
Author(s):  
Marijana Majić ◽  
Lidija Ćurković
Keyword(s):  
Fracture Toughness ◽  
Vickers Indentation ◽  
Alumina Ceramics ◽  
Indentation Technique

Evaluation of Brittle Layers Obtained by Boriding on AISI H13 Steels

2009 ◽  
Vol 65 ◽  
pp. 47-52 ◽  
Author(s):  
N. López-Perrusquia ◽  
Ivan Campos-Silva ◽  
José Martínez-Trinidad ◽  
A. Avilés ◽  
E. Alvárez-Castañeda ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Boride Layer ◽  
Vickers Indentation ◽  
Indentation Technique ◽  
Substrate Interface ◽  
Aisi H13 ◽  
Boriding Process ◽  
Brittle Layers ◽  
Poor Adhesion ◽  
Borided Steel

The fracture toughness of AISI H13 borided steel and the strength adhesion of the coated system were estimated in the present work. The formation of the layers was carried out by the powder pack boriding process at 1273 K with 8 h of treatment. The fracture toughness (KC) of the layer is estimated at 25 and 45 m from the surface using four different Vickers indentation loads. The KC values were estimated by the extension of Palmqvist cracks parallel and perpendicular to the surface obtained at the indentation corners. The adherence of the layer/substrate was evaluated in qualitative form through the Rockwell-C indentation technique. The results obtained by both techniques, show, in first instance, that the fracture toughness of the boride layer can be expressed in the form (KC) (π/2) > (KC) > (KC) (0). Also, high delamination is obtained around the Rockwell-C indentation prints that denote poor adhesion in the coating-substrate interface.

The Fracture Toughness and DBTT of MoB Particle-Reinforced MoSi2 Composites

2007 ◽  
Vol 280-283 ◽  
pp. 1471-1474
Author(s):  
Zhi Xiong ◽  
Gang Wang ◽  
Wan Jiang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Room Temperature ◽  
Probable Mechanism ◽  
Vickers Indentation ◽  
Indentation Technique ◽  
Testing Method ◽  
Temperature Fracture

The room temperature fracture toughness and the high temperature DBTT of MoB particle-reinforced MoSi2 composites were investigated using Vickers indentation technique and MSP testing method， respectively. Modified Small Punch (MSP) test is a method for evaluation of mechanical properties using very small specimens, and it’s appropriate for the determination of strength and DBTT. It was found that the approximate fracture toughness of the composite is 1.3 times that of monolithic MoSi2, and its DBTT is 100°C higher than that of monolithic MoSi2 materials. Cracks deflection is a probable mechanism responsible for this behavior.

Evaluating microhardness of plasma sprayed Al2O3coatings using Vickers indentation technique

2007 ◽  
Vol 40 (22) ◽  
pp. 7090-7096 ◽  
Author(s):  
Zhijian Yin ◽  
Shunyan Tao ◽  
Xiaming Zhou ◽  
Chuanxian Ding
Keyword(s):  
Vickers Indentation ◽  
Indentation Technique ◽  
Plasma Sprayed

Nondestructive Estimation of Fracture Toughness Using Instrumented Indentation Technique

2008 ◽  
Vol 385-387 ◽  
pp. 893-896
Author(s):  
Kyung Woo Lee ◽  
Hyun Uk Kim ◽  
Sang Wook Park ◽  
Jung Suk Lee ◽  
Kwang Ho Kim ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Damage Mechanics ◽  
Volume Fraction ◽  
Fracture Initiation ◽  
Continuum Damage Mechanics ◽  
Instrumented Indentation ◽  
Initiation Point ◽  
Indentation Technique ◽  
Proposed Model ◽  
Main Ideas

This study focused on the determination of fracture toughness by instrumented indentation technique. A theoretical model to estimate the fracture toughness of ductile materials is proposed and used to verify those results. Modeling of IIT to evaluate fracture toughness is based on two main ideas; the energy input up to characteristic fracture initiation point during indentation was correlated with material’s resistance to crack initiation and growth, and this characteristic fracture initiation point was determined by concepts of continuum damage mechanics. The estimated fracture toughness values obtained from the indentation technique showed good agreement with those from conventional fracture toughness tests based on CTOD. In addition, we confirmed that the proposed model can be also applied in the brittle material through modification of void volume fraction.

scholarly journals Sintering of alumina ceramics reinforced with a bioactive glass of 3CaO.P2O5-SiO2-MgO system

Cerâmica ◽  
2015 ◽  
Vol 61 (358) ◽  
pp. 160-167 ◽  
Author(s):  
A. W. Huang ◽  
C. Santos ◽  
R. O. Magnago ◽  
R. F. F. Silva ◽  
K. Strecker ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Relative Density ◽  
Transient Liquid Phase ◽  
Xrd Analysis ◽  
Alumina Ceramics ◽  
Crystalline Phases ◽  
Powder Mixtures ◽  
Solid State Sintering ◽  
Sintering Condition

<p>Alumina-based ceramics, Al<sub>2</sub>O<sub>3</sub>, exhibit a combination of properties which favor its use as biomaterial, specifically as structural dental prosthesis. Its most important properties as biomaterial are its elevated hardness, chemical stability and biocompatibility. Usually, Al<sub>2</sub>O<sub>3</sub> is processed by solid-state sintering at a temperature of about 1600 <sup>o</sup>C, but it is very difficult to eliminate the porosity due to its diffusional characteristics. The objective of this work was the development and characterization of sintered Al<sub>2</sub>O<sub>3</sub> ceramics, densified with a transient liquid phase formed by a bioactive 3CaO.P<sub>2</sub>O<sub>5</sub>-SiO<sub>2</sub>-MgO glass. Powder mixtures of 90 wt.% Al<sub>2</sub>O<sub>3</sub> and 10 wt.% bioglass were milled, compacted and sintered at 1200 <sup>o</sup>C to 1450 <sup>o</sup>C. Comparatively, monolithic Al<sub>2</sub>O<sub>3</sub> samples were sintered at 1600 <sup>o</sup>C/120 min. The sintered specimens were characterized by relative density, crystalline phases, microstructure and mechanical properties. The results indicate that the specimen sintered at 1450 <sup>o</sup>C/120 min present the best properties. Under this sintering condition, a relative density of 95% was reached, besides hardness higher than 9 GPa and fracture toughness of 6.2 MPa.m<sup>1/2</sup>. XRD analysis indicate alumina (αAl<sub>2</sub>O<sub>3</sub>), whitlockite (3CaO.P<sub>2</sub>O<sub>5</sub>) and diopsite [3(Ca,Mg)O.P<sub>2</sub>O<sub>5</sub>], as crystalline phases. Comparatively, monolithic sintered Al<sub>2</sub>O<sub>3</sub> samples presented 92% of relative density with 17.4 GPa and 3.8 MPa.m<sup>1/2</sup> of hardness and fracture toughness respectively.</p>

scholarly journals Elastic Modulus, Strength and Fracture Toughness of Alumina Ceramics Containing Pores.

2002 ◽  
Vol 110 (1282) ◽  
pp. 554-559 ◽  
Author(s):  
Masahiro ASHIZUKA ◽  
Eiichi ISHIDA ◽  
Taishi MATSUSHITA ◽  
Masahiro HISANAGA
Keyword(s):  
Fracture Toughness ◽  
Elastic Modulus ◽  
Alumina Ceramics
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