Mechanical behavior of zirconia/alumina composites

2005 ◽  
Vol 31 (1) ◽  
pp. 39-46 ◽  
Author(s):  
S.R. Choi ◽  
N.P. Bansal
Keyword(s):  
Mechanical Behavior ◽  
Alumina Composites

scholarly journals Nacre-like Alumina Composites Based on Heteroaggregation

2020 ◽  
Author(s):  
Mariana Muñoz ◽  
Manuella Cerbelaud ◽  
Arnaud Videcoq ◽  
Hassan Saad ◽  
Alexandre Boulle ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Mechanical Behavior ◽  
Colloidal Suspensions ◽  
High Strength ◽  
Ceramic Composites ◽  
Anisotropic Particles ◽  
High Toughness ◽  
High Stiffness ◽  
Brick And Mortar ◽  
Alumina Composites

<div> <div> <div> <p>High strength and high toughness are usually mutually exclusive in materials. Among all material classes, ceramics exhibit a high stiffness and strength, but they present a limited plastic deformation, which results in a moderate toughness. However, tough ceramics have been obtained using anisotropic particles organized in a "brick and mortar" microstructure, inspired by the structure of the natural nacre. Here, we propose to build nacre-like ceramic composites from colloidal suspensions using heteroaggregation of particles. Two different shaping processes are used: direct settling of suspensions or freeze-granulation. After sintering, in both cases, the platelets alignment is very good, close to that of platelets in natural nacre, with a slightly better one noted for direct settling. Despite a better platelet alignment, the toughness is lower than in previous studies showing that further improvement of the interfacial phases present in the material must now be considered to reinforce its mechanical behavior. </p> </div> </div> </div>

Fracture behavior of Al2O3/SiC-platelet composites

1996 ◽  
Vol 11 (10) ◽  
pp. 2528-2535 ◽  
Author(s):  
M. Belmonte ◽  
J. S. Moya ◽  
P. Miranzo ◽  
D. Nguyen ◽  
J. Dubois ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Mechanical Behavior ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Impurity Content ◽  
High Viscosity ◽  
Large Matrix ◽  
Alumina Composites ◽  
Shock Resistance

Mechanical behavior of hot-pressed SiC platelet reinforced alumina composites has been analyzed as a function of SiC platelet content for two different alumina matrix powders. Fracture toughness and flexural strength at temperatures ranging from 25 to 1200 °C, R-curve behavior, and thermal shock resistance have been determined. Small differences in the impurity content of the starting Al2O3 powders strongly determine the microstructure and the mechanical behavior of Al2O3/SiC-platelet composites. Low alkali content alumina led to composites with large matrix grain size which presented spontaneous microcracking. At high temperature, a high viscosity liquid phase is formed that shields cracks enhancing mechanical properties and R-curve behavior. A small amount of impurities reduced Al2O3 matrix grain size and avoided spontaneous microcracking. Enhanced fracture toughness (up to 30%) at room temperature, R-curve behavior, and thermal shock resistance were achieved for these materials.

scholarly journals Nacre-like Alumina Composites Based on Heteroaggregation

2020 ◽  
Author(s):  
Mariana Muñoz ◽  
Manuella Cerbelaud ◽  
Arnaud Videcoq ◽  
Hassan Saad ◽  
Alexandre Boulle ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Mechanical Behavior ◽  
Colloidal Suspensions ◽  
High Strength ◽  
Ceramic Composites ◽  
Anisotropic Particles ◽  
High Toughness ◽  
High Stiffness ◽  
Brick And Mortar ◽  
Alumina Composites

<div> <div> <div> <p>High strength and high toughness are usually mutually exclusive in materials. Among all material classes, ceramics exhibit a high stiffness and strength, but they present a limited plastic deformation, which results in a moderate toughness. However, tough ceramics have been obtained using anisotropic particles organized in a "brick and mortar" microstructure, inspired by the structure of the natural nacre. Here, we propose to build nacre-like ceramic composites from colloidal suspensions using heteroaggregation of particles. Two different shaping processes are used: direct settling of suspensions or freeze-granulation. After sintering, in both cases, the platelets alignment is very good, close to that of platelets in natural nacre, with a slightly better one noted for direct settling. Despite a better platelet alignment, the toughness is lower than in previous studies showing that further improvement of the interfacial phases present in the material must now be considered to reinforce its mechanical behavior. </p> </div> </div> </div>

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

The influence of the addition of ground olive stone on the thermo-mechanical behavior of compressed earth blocks

2020 ◽  
Vol 108 (2) ◽  
pp. 203
Author(s):  
Samia Djadouf ◽  
Nasser Chelouah ◽  
Abdelkader Tahakourt
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Mechanical Behavior ◽  
Agricultural Waste ◽  
Hydraulic Press ◽  
Dry Density ◽  
Olive Stone ◽  
Compressed Earth Blocks ◽  
Clay Matrix ◽  
Earth Blocks

Sustainable development and environmental challenges incite to valorize local materials such as agricultural waste. In this context, a new ecological compressed earth blocks (CEBS) with addition of ground olive stone (GOS) was proposed. The GOS is added as partial clay replacement in different proportions. The main objective of this paper is to study the effect of GOS levels on the thermal properties and mechanical behavior of CEB. We proceeded to determining the optimal water content and equivalent wet density by compaction using a hydraulic press, at a pressure of 10 MPa. The maximum compressive strength is reached at 15% of the GOS. This percentage increases the mechanical properties by 19.66%, and decreases the thermal conductivity by 37.63%. These results are due to the optimal water responsible for the consolidation and compactness of the clay matrix. The substitution up to 30% of GOS shows a decrease of compressive strength and thermal conductivity by about 38.38% and 50.64% respectively. The decrease in dry density and thermal conductivity is related to the content of GOS, which is composed of organic and porous fibers. The GOS seems promising for improving the thermo-mechanical characteristics of CEB and which can also be used as reinforcement in CEBS.

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