Thermal Shock Behavior of Fiber-Reinforced Ceramic Composites

1994 ◽  
Vol 365 ◽  
Author(s):  
Raj N. Singh ◽  
Hongyu Wang
Keyword(s):  
Thermal Shock ◽  
Thermal Stresses ◽  
Fiber Type ◽  
Damage Mechanism ◽  
Ceramic Composites ◽  
Fiber Reinforced ◽  
Quench Temperature ◽  
Monolithic Ceramics ◽  
Thermal Shock Behavior ◽  
Original Strength

ABSTRACTThe influence of fiber type and method of composite fabrication on the thermal shock behavior of 2-D fiber-reinforced ceramic composites is studied. Thermal shock tests are performed using a water quench technique, and thermal shock damage is characterized by both destructive and nondestructive techniques. It is shown that the composites possessed superior resistance to thermal shock damage than the monolithic ceramics. Catastrophic failure due to severe thermal stresses is prevented in composites and a significant portion of their original strength is retained at a quench temperature difference up to 1000°C. These results along with an analysis of the thermal shock damage mechanism based on the destructive and nondestructive tests is described.

Thermal shock behavior of SiC whisker reinforced Si3N4/BN fibrous monolithic ceramics

2003 ◽  
Vol 57 (11) ◽  
pp. 1670-1674 ◽  
Author(s):  
ShuQin Li ◽  
Yong Huang ◽  
YongMing Luo ◽  
ChangAn Wang ◽  
CuiWei Li
Keyword(s):  
Thermal Shock ◽  
Monolithic Ceramics ◽  
Thermal Shock Behavior

Damage Assessment of Mullite Ceramic Foams in Radiant Gas Burners

2008 ◽  
Vol 587-588 ◽  
pp. 99-103 ◽  
Author(s):  
Fernando A. Costa Oliveira
Keyword(s):  
Thermal Shock ◽  
Thermal Stresses ◽  
Damage Mechanism ◽  
Ceramic Foam ◽  
Chemical Degradation ◽  
Mullite Ceramic ◽  
Open Cell ◽  
Ceramic Foams ◽  
Chemical Attack ◽  
Combustion Environment

The damage imposed on open-cell mullite ceramic foams was evaluated in pre-mixed radiant gas burners. After exposure to the prevailing combustion environment, foams suffered moderate strength degradation as a result of thermal stresses being imposed on the material during service. There was evidence of chemical attack during combustion although thermal shock measurements suggest that damage sustained by the foams results mainly from thermal shock rather than chemical degradation. Indeed, samples from burners subjected to ageing tests did not show additional damage compared to those subjected to short ageing tests indicating that most of damage occurred during start-up. For comparison purposes, a set of ceramic foam samples were subjected to a water quench test so that the extent to which the foams were damage by exposure to the combustion environment, under well controlled conditions, could be established. The strength retained after thermal shock by open-cell mullite foams decreased gradually with increasing quench temperatures. This suggests a cumulative damage mechanism reflecting an increase in damage throughout the material rather than sudden failure owing to propagation of pre-existing cracks along a plane. Damage in mullite foams was mainly localised at the top layer of the burners where higher temperatures and steeper thermal gradients were imposed on the material. Surprisingly, needle-like mullite crystals with a large aspect ratio were also found to have grown at the surface of the burners via a vapour feed gas-liquid catalyst-solid needle-like growth (VLS) mechanism.

Thermal Cycling, Thermal Aging and Thermal Shock Behavior of Nicalon-Fiber Reinforced Glass Matrix Composites

1998 ◽  
Vol 164-165 ◽  
pp. 345-350 ◽  
Author(s):  
Aldo Roberto Boccaccini ◽  
H. Kern ◽  
Jolanta Janczak-Rusch ◽  
Clive.B. Ponton ◽  
Krish K. Chawla
Keyword(s):  
Thermal Cycling ◽  
Thermal Shock ◽  
Thermal Aging ◽  
Glass Matrix ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Thermal Shock Behavior ◽  
Glass Matrix Composites

Thermal Shock Behaviour of Open-Cell Cordierite Foams

2006 ◽  
Vol 514-516 ◽  
pp. 764-767 ◽  
Author(s):  
Fernando A. Costa Oliveira ◽  
Susana Dias ◽  
Jorge Cruz Fernandes
Keyword(s):  
Flexural Strength ◽  
Thermal Shock ◽  
Thermal Stresses ◽  
Damage Mechanism ◽  
Replication Process ◽  
Open Cell ◽  
Ceramic Foams ◽  
Sudden Decrease ◽  
Shock Behaviour ◽  
Thermal Shock Behaviour

Open-cell ceramic foams are being considered for a variety of applications owing to their high permeability and low weight, including molten metal filters, catalytic substrates and radiant burners. In these applications, foams are exposed to high temperatures and thermal gradients and thus the materials used require resistance to severe thermal stresses during service. Unfortunately, little is known about the thermal shock behaviour of cordierite foams when subjected to sudden changes in temperature. The objective of the present study was to investigate the thermal shock behaviour of two kinds of cordierite-based ceramic foams manufactured by the replication process. Thermal shock experiments were carried out by rapidly transferring the heated samples from a resistance furnace to a quenching bath containing distilled water followed by measuring of the retained flexural strength. Unlike dense cordierite samples that showed a sudden decrease in flexural strength at quench temperature differences above 325 K, the strength retained after thermal shock by open-cell cordierite foams decreased gradually with increasing quench temperatures. This suggests a cumulative damage mechanism reflecting an increase in damage throughout the material rather than sudden failure owing to propagation of pre-existing cracks.

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