Microstructural aspects of Thermal Stress Resistance of high-strength engineering ceramics Part II: Influence of microstructure on thermal shock resistance of high-strength engineering ceramics

1985 ◽  
Vol 16 (2) ◽  
pp. 45-55 ◽  
Author(s):  
G. Ziegler
Keyword(s):  
Thermal Stress ◽  
Thermal Shock ◽  
Stress Resistance ◽  
Thermal Shock Resistance ◽  
High Strength ◽  
Engineering Ceramics ◽  
Shock Resistance

Improvement on Thermal Shock Resistance of Ceramic Components by Using Self-Healing

2010 ◽  
Author(s):  
Wataru Nakao
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Thermal Shock ◽  
Stress Fracture ◽  
Thermal Shock Resistance ◽  
Self Healing ◽  
Quenching Rate ◽  
Ceramic Components ◽  
Shock Resistance ◽  
Quenching Method

Availability of self-healing on the thermal shock resistance of ceramic components was investigated. Using gas quenching method, the crack-healed alumina-18 vol% SiC composite, which has excellent self-healing ability, was applied to thermal shock of the arbitrary quenching rate. The procedure could give rise to the thermal stress fracture at high temperature. The critical quenching rate at thermal stress fracture of the healed specimen was found to be 6.47 K/s, corresponding to the thermal stress of 452.3 MPa. Alternatively, that of the cracked specimen was found to be 5.02 K/s, corresponding to the thermal stress of 350 MPa. From the obtained results, usage of self-healing was confirmed to improve extremely thermal shock resistance. The present result suggests that usage of self-healing gives a large advantage to design the high temperature ceramic components, because the mechanically reliable design and thermal shock resistance cannot coexist due to low thermal conductivity.

Fabrication, Microstructure, and Properties of Zirconium Diboride Matrix Ceramic

2013 ◽  
pp. 354-412 ◽  
Author(s):  
Zhi Wang ◽  
Zhanjun Wu
Keyword(s):  
Thermal Stress ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Zirconium Diboride ◽  
Isothermal Oxidation ◽  
Rate Of Change ◽  
Oxide Layers ◽  
Sic Ceramic ◽  
Shock Resistance ◽  
Quenching Method

The crystal structure, synthesis, and densification of zirconium diboride (ZrB2) are summarized in detail. In this chapter, ZrB2-ZrC-SiC ceramic was synthesized by reactive hot pressing a mixture of Zr, B4C, and Si powders. The thermal shock resistance of the ZrB2-SiC-ZrC ceramic was estimated by the water-quenching method and was significantly greater than that of a ZrB2-15vol.% SiC ceramic. The isothermal oxidation of the ZrB2-SiC-ZrC ceramic was carried out in static air at constant temperatures of 1000±15, 1200±15, and 1400±15 ºC for different amounts of time at each temperature. The mechanism of strength increase for the oxidized specimen indicated that the strength increased with the reaction rate, which was related to the rate of change in volume induced by reaction, initial crack geometry, elastic modulus, and surface free energy. The formation of oxide layers resulted in (I) repair of surface flaws, (II) increase in flexural strength, (III) appearance of a compressive stress zone beneath the surface oxide layers, (IV) decrease in thermal stress, and (V) consumption of thermal stress. These five aspects were favorable to the improvement of the thermal shock resistance of the ZrB2-SiC-ZrC ceramic. The isothermal oxidation of the ZrB2-SiC-ZrC ceramic was carried out in static air at 1600±15 ºC. In the different oxidation stages, quantitative models were proposed for predicting oxidation kinetics.

Preparation of corundum-mullite refractories with lightweight, high strength and high thermal shock resistance

Materialia ◽  
2019 ◽  
Vol 8 ◽  
pp. 100517
Author(s):  
Yongqiang Chen ◽  
Guoqi Liu ◽  
Qiang Gu ◽  
Sai Li ◽  
Bingbing Fan ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
High Strength ◽  
Shock Resistance ◽  
High Thermal Shock Resistance

The Study of Optimum Shape to Evaluation for Thermal Shock Behavior of Graphite

2006 ◽  
Vol 326-328 ◽  
pp. 915-918 ◽  
Author(s):  
Song Heo Koo ◽  
Young Shin Lee
Keyword(s):  
Mechanical Property ◽  
Thermal Stress ◽  
Thermal Shock ◽  
Laser Irradiation ◽  
Power Density ◽  
Thermal Shock Resistance ◽  
Central Area ◽  
Optimum Shape ◽  
Transient Temperature ◽  
Shock Resistance

The purpose of the present study is to evaluate thermal shock properties of the ATJ graphite using laser irradiation techniques. Cracks of thermal shock specimens are initiated by maximum tensile stress field. Thermal shock resistance of the ATJ graphite is correlated with thermal parameter and mechanical property. To simulate the thermal stress conditions of rocket nozzle throat for the evaluation of the thermal shock resistance of ATJ graphite, the laser irradiation was applied at the central area of disk specimen. Thermal shock resistance was related to the geometry, the maximum stress, and the thermal and mechanical property. Also the analyses of transient temperature and thermal stress were performed by the finite element method with nonlinear code ABAQUS. Analyses were specially performed for several kinds of shape to determine the minimum power density which could be cracked the specimen. The shape of the thermal shock specimen which was cracked under the lower power density was obtained and the result will be proved to the test.

Development of High Performance Mid-Temperature Burnt Al2O3-ZrO2-C Slide Gates

2012 ◽  
Vol 510 ◽  
pp. 689-693
Author(s):  
Wei Li ◽  
Hou Xing Zhang ◽  
Ze Ming Tong ◽  
Yan Ming Li
Keyword(s):  
Thermal Stress ◽  
Thermal Shock ◽  
Molten Steel ◽  
Thermal Shock Resistance ◽  
High Performance ◽  
Slide Gate ◽  
Refining Process ◽  
Thermal Gradients ◽  
Edge Part ◽  
Shock Resistance

Slide gates are installed at the bottom of a ladle or tundish to control the flow of molten steel. It plays an important role in ladle refining process and continuous casting. Al2O3-ZrO2-C refractories are widely used as slide gate materials due to its excellent corrosion and thermal shock resistance. At the start of casting, molten steel almost 1600°C passes through the bore of slide gate, the plate is rapidly heated up, the temperature difference between the bore and edge part, the slide gates are subject to large thermal gradients, so there is large thermal stress in the plate. This paper will show the results of our improved slide gates with good thermal shock resistance.

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