Crack healing, reopening and thermal expansion behavior of Al2TiO5 ceramics at high temperature

2007 ◽  
Vol 27 (2-3) ◽  
pp. 1431-1434 ◽  
Author(s):  
Hyung Chul Kim ◽  
Kee Sung Lee ◽  
Oh Seong Kweon ◽  
Christos G. Aneziris ◽  
Ik Jin Kim
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Crack Healing ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior

EFFECT OF HIGH TEMPERATURE DEFORMATION ON THE LOW THERMAL EXPANSION BEHAVIOR OF FE-29%NI-17%CO ALLOY

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6016-6021 ◽  
Author(s):  
K. A. LEE ◽  
J. NAMKUNG ◽  
M. C. KIM
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Strain Rate ◽  
Strain Rate Range ◽  
Theoretical Explanation ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Thermal Expansion Behavior ◽  
Low Thermal Expansion ◽  
Expansion Behavior

The effect of high temperature deformation on the low thermal expansion property of Fe -29 Ni -17 Co alloy was investigated in the compressive temperature range of 900~1300°C at a strain rate range of 25 ~ 0.01 sec. -1. The thermal expansion coefficient (α30~400) generally increased with increasing compressive temperature. In particular, α30~400 increased remarkably as the strain rate decreased at temperatures above 1100°C. Note, however, that α30~400 at low compressive temperatures (900°C and 1000°C) increased abnormally at high strain rates. Based on the investigation of various possibilities of change in low thermal expansion behavior, the experimental results indicated that both the appearance of the α phase and evolution of grain size due to hot compression clearly influenced the low thermal expansion behavior of this invar-type alloy. The correlation between the microstructural cause and invar phenomena and theoretical explanation for the low thermal expansion behavior of Fe -29% Ni -17% Co were also suggested.

High temperature structural and thermal expansion behavior of pyrochlore-type praseodymium zirconate

2015 ◽  
Vol 40 (45) ◽  
pp. 15672-15678 ◽  
Author(s):  
R. Shukla ◽  
K. Vasundhara ◽  
P.S.R. Krishna ◽  
A.B. Shinde ◽  
S.K. Sali ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Pyrochlore Type

Crack Healing, Reopening and Thermal Expansion Behavior of Al2TiO5 Ceramics at High Temperature

2007 ◽  
Vol 336-338 ◽  
pp. 2448-2450 ◽  
Author(s):  
Ik Jin Kim ◽  
Kee Sung Lee ◽  
Christos G. Aneziris
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Low Temperature ◽  
Grain Boundary ◽  
Crack Healing ◽  
Thermal Expansion Anisotropy ◽  
Low Thermal Expansion ◽  
Micro Cracks ◽  
Expansion Behavior ◽  
The Individual

The low thermal expansion (α25-1100oC = 0.05 ~ 1.6 × 10–6/K) of Al2TiO5 ceramics are apparently due to a combination of grain boundary micro cracking caused by the large thermal expansion anisotropy of the crystal axes of the Al2TiO5 phase. During the reheating run, the individual crystallites expanded at low temperature; thus, the solid volume of the specimen expanded into the micro cracks, where as the macroscopic dimensions remained almost unchanged. As a result, the material expanded very little. The micro cracks closed at higher temperatures. This result is closely related to relatively steeper thermal expansion curves.

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