Microstructure and fracture toughness of nickel particle toughened alumina matrix composites

1996 ◽  
Vol 31 (4) ◽  
pp. 875-880 ◽  
Author(s):  
Xudong Sun ◽  
J. A. Yeomans
Keyword(s):  
Fracture Toughness ◽  
Nickel Particle ◽  
Matrix Composites ◽  
Alumina Matrix

Improvement of flexure strength and fracture toughness in alumina matrix composites reinforced with carbon nanotubes

2009 ◽  
Vol 517 (1-2) ◽  
pp. 293-299 ◽  
Author(s):  
Sung Wan Kim ◽  
Won Sub Chung ◽  
Kee-Sun Sohn ◽  
Chang-Young Son ◽  
Sunghak Lee
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Matrix Composites ◽  
Alumina Matrix ◽  
Flexure Strength

Sintering temperature-microstructure-property relationships of alumina matrix composites with silicon carbide and silica additives

2017 ◽  
Vol 24 (4) ◽  
pp. 495-500 ◽  
Author(s):  
Apichart Limpichaipanit ◽  
Sukanda Jiansirisomboon ◽  
Tawee Tunkasiri
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Grain Size ◽  
Fracture Surface ◽  
Sintering Temperature ◽  
Matrix Composites ◽  
Reaction Sintering ◽  
Alumina Matrix ◽  
Powder Mixtures ◽  
Ceramic Samples

AbstractAlumina-based composites were fabricated by reaction sintering from two different sintering powder mixtures: alumina with silica (SiO2) and alumina with silicon carbide (SiC; to allow oxidation to form SiO2). After sintering, SiO2 underwent complete reaction to form alumina/mullite composites. In terms of microstructure, the density and grain size of ceramic samples were investigated. The density of the composites prepared by alumina and SiC was lower than those of alumina and the composites prepared by alumina and SiO2. The grain size increased as the sintering temperature increased. In terms of mechanical properties, fracture surfaces, hardness, and fracture toughness were investigated. It was found that the fracture surface of alumina was rather intergranular, whereas the fracture surface of the composites was more transgranular. The hardness of the composites was higher than that of alumina at the same sintering temperature. However, the fracture toughness of the composites was not significantly different compared to that of alumina.

Mechanical Properties of Alumina Matrix Composites due to a Combination of Sr- and Ca-Hexaluminates

2011 ◽  
Vol 484 ◽  
pp. 102-105
Author(s):  
Wantanee Buggakupta
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Matrix Composites ◽  
Alumina Matrix ◽  
Alkali Earth ◽  
Intermediate Phases ◽  
Calcium Hexaluminate ◽  
Wide Range ◽  
Dispersed Phases ◽  
Monolithic Alumina

Alumina matrix composites have been successfully used in a wide range of applications for decades. Even alumina itself provides several desirable properties e.g. strength, chemical and thermal stability together with hardness, its toughness is still to be concerned. An addition of some intermediate phases such as alkali earth hexaluminates can enhance fracture toughness according to their unique morphology. This work investigated a variation in mechanical properties of alumina as a presence of two types of dispersed phases: strontium hexaluminate and calcium hexaluminate. The preformed hexaluminate compounds were prepared from a powder mixture of the alkali earth carbonates and alumina. The preformed hexaluminates were then added into alumina, followed by pressureless sintered at 1600 oC for 2 hours in air. A change in mechanical properties of alumina according to types and amount of additives as well as the ratio of calcium hexaluminate to strontium hexaluminate compounds on was studied. The composites with the relative density of at least 93%TD were achieved. Both hexaluminates resulted in a significant increase in fracture toughness relative to the monolithic alumina while they slightly affected on hardness and strength. When the ratio of calcium hexaluminate to strontium hexaluminate in alumina matrix was considered, a rise in fracture toughness strongly depended on the fraction of calcium hexaluinate. The calcium hexaluminate tended to be more efficient additive in order to strengthen alumina than that of the strontium ones

Comparative Analysis of Fracture Toughness Obtained by Different Techniques in Alumina Matrix - Dispersed TZP Zirconia Composites

2016 ◽  
Vol 869 ◽  
pp. 46-51
Author(s):  
Daniel Alessander Nono ◽  
Eron Fernandes da Silva ◽  
Maria do Carmo de Andrade Nono ◽  
Francisco Piorino Neto ◽  
Sergio Luiz Mineiro
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Ceramic Composites ◽  
Alumina Matrix ◽  
Single Edge ◽  
Chemical Inertness ◽  
Edge Notch ◽  
Properties Of Materials ◽  
Experimental Values ◽  
Benefit Cost

The fracture toughness is one of the requirements for mechanical properties of materials for use in satellites. The ceramic TZP zirconia (tetragonal zirconia polycrystals) have been investigated for applications in ballistic armor. Due to the chemical inertness and fracture toughness, this material has the potential to act as a screen against impacts of micrometeorites and space debris. The ceramic composites of alumina-zirconia 3Y-TZP (tetragonal zirconia polycrystals doped with 3 mol% ytria ) are the materials with the best benefit / cost for this application. This paper presents and discusses the results obtained from the use of two techniques for determining fracture toughness. The composite alumina - 18.5% of 3Y-TZP zirconia nanoparticles obtained from deflocculated powders have been tested for Vickers and the SEVNB penetration method (Single-Edge-Notch Beam V) to obtain the fracture toughness values (KIC). The KIC values obtained were analyzed due to the lower dispersion of experimental values. The SEVNB method showed better reliability in determining the toughness values in the studied ceramics.

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