TY - JOUR
T1 - The temperature distribution in plasma-sprayed thermal-barrier coatings during crack propagation and coalescence
AU - Dong, Hui
AU - Han, Yan
AU - Zhou, Yong
AU - Li, Xiao
AU - Yao, Jian Tao
AU - Li, Yan
N1 - Publisher Copyright:
© 2018 by the authors.
PY - 2018
Y1 - 2018
N2 - A Finite-Element Model (FEM) for thermal-barrier coatings was employed to elaborate the temperature distribution on yttria-stabilized zirconia (YSZ) free surface during cracks coalescing, then the influence of sintering of YSZ induced by heat-transfer overlapping on energy release rate was quantificationally evaluated. A three-dimensional model including three layers was fabricated. Two types of cracks, with and without depth variations in YSZ coating, were introduced into the model, respectively. The temperature rise of YSZ coating over the crack is independent of each other at the beginning of crack propagation. As crack distance shortens, the independent temperature-rise regions begin to overlap, while maximum temperature is still located at the crack center before crack coalescence. The critical distance that the regions of temperature rise, just overlapping, is the sum of half lengths of two coalescing cracks (i.e., a1 + a2), which is independent of cracking path. The maximum temperature in YSZ sharply increases once cracks coalesce. Compared with one delamination crack, the effective energy-release rate induced by heat-transfer overlapping increases in the range of 0.2%-15%, depending on crack length and crack distance, which is on some level comparable to that of deterioration of thermal expansion misfit induced by temperature jump between crack faces.
AB - A Finite-Element Model (FEM) for thermal-barrier coatings was employed to elaborate the temperature distribution on yttria-stabilized zirconia (YSZ) free surface during cracks coalescing, then the influence of sintering of YSZ induced by heat-transfer overlapping on energy release rate was quantificationally evaluated. A three-dimensional model including three layers was fabricated. Two types of cracks, with and without depth variations in YSZ coating, were introduced into the model, respectively. The temperature rise of YSZ coating over the crack is independent of each other at the beginning of crack propagation. As crack distance shortens, the independent temperature-rise regions begin to overlap, while maximum temperature is still located at the crack center before crack coalescence. The critical distance that the regions of temperature rise, just overlapping, is the sum of half lengths of two coalescing cracks (i.e., a1 + a2), which is independent of cracking path. The maximum temperature in YSZ sharply increases once cracks coalesce. Compared with one delamination crack, the effective energy-release rate induced by heat-transfer overlapping increases in the range of 0.2%-15%, depending on crack length and crack distance, which is on some level comparable to that of deterioration of thermal expansion misfit induced by temperature jump between crack faces.
KW - Crack propagation
KW - Cracking path
KW - Plasma spraying
KW - Temperature distribution
KW - Thermal-barrier coatings (TBC)
KW - YSZ sintering
UR - https://www.scopus.com/pages/publications/85065733648
U2 - 10.3390/COATINGS8090311
DO - 10.3390/COATINGS8090311
M3 - 文章
AN - SCOPUS:85065733648
SN - 2079-6412
VL - 8
JO - Coatings
JF - Coatings
IS - 9
M1 - 311
ER -