Effect of beam angle on HAZ, recast and oxide layer characteristics in laser drilling of TBC nickel superalloys

H. K. Sezer; L. Li; M. Schmidt; A. J. Pinkerton; B. Anderson; P. Williams

doi:10.1016/j.ijmachtools.2006.01.010

Effect of beam angle on HAZ, recast and oxide layer characteristics in laser drilling of TBC nickel superalloys

H. K. Sezer, L. Li, M. Schmidt, A. J. Pinkerton, B. Anderson, P. Williams

Research output: Contribution to journal › Article › peer-review

Abstract

Industrial applications of laser drilling include the production of cooling holes at acute angles in certain parts of the aero-engine components. These parts are often covered with ceramic thermal barrier coatings (TBC) to protect them from reaching excessive temperatures in hot engine environments. Acute angle TBC drilling brings three major simultaneous complications to the process. These are: (i) multi-layer drilling, (ii) non-symmetrical geometry and melt ejection, and (iii) increased depth of drilling. In a previous investigation by the authors, delamination of TBC was found as a main problem of angled drilling and mechanisms involved were studied. In the present study, implications of these difficulties on the hole quality is investigated through a comparative study of vertical and acute angle drilled holes. Characteristics of recast layer, heat-affected zone (HAZ), oxide layer and TBC delamination are investigated. Variation of these metallurgical characteristics with the depth of the hole is evaluated. Results for vertical and inclined holes are compared. The extent of HAZ, recast layer and oxide layer is seen to vary significantly with location and is found increasing with decreasing drilling angle to surface. Numerical simulation of pulsed laser heating of TBC Nimonic 263 was carried out for acute angle drilling with assist gas considerations. Results from the simulation suggested that the total heat transfer rate is higher on the leading edge side than the trailing edge of the heated region. Experimentally observed larger HAZ on leading edge side and larger recast layer on trailing edge side are explained by the analysis of heat flow characteristics obtained with the model. © 2006 Elsevier Ltd. All rights reserved.

Original language	English
Pages (from-to)	1972-1982
Number of pages	10
Journal	International Journal of Machine Tools and Manufacture
Volume	46
Issue number	15
DOIs	https://doi.org/10.1016/j.ijmachtools.2006.01.010
Publication status	Published - Dec 2006

Keywords

Heat affected zone
Laser drilling
Recast layer
Thermal barrier coating

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10.1016/j.ijmachtools.2006.01.010

LPRC: Laser Processing Research Centre Impact
Allegre, O. (PI), Crosby, D. (PI), Domingos, M. (PI), Francis, J. (PI), Gillen, D. (PI), Guo, W. (PI), Li, L. (PI), Mativenga, P. (PI), Rogers, B. D. (PI), Whitehead, D. (PI), Wilson, D. (PI), Zhong, S. (PI), Mirhosseini, N. (Researcher), Ouyang, J. (Researcher), Huang, Y. (Researcher), Wei, C. (Researcher), Cheng, D. (PGR student), Suryo Pratomo, E. (PGR student), Zhang, Z. (PGR student), Li, Z. (PGR student), Mo, H. (PGR student), Zhu, M. (PGR student), Li, Q. (PGR student), Liu, W. (PGR student), Wang, L. (PGR student), Guo, H. (PGR student), Heinemann, R. (PI) & Liu, Z. (PI)
1/04/00 → …
Project: Research

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title = "Effect of beam angle on HAZ, recast and oxide layer characteristics in laser drilling of TBC nickel superalloys",

abstract = "Industrial applications of laser drilling include the production of cooling holes at acute angles in certain parts of the aero-engine components. These parts are often covered with ceramic thermal barrier coatings (TBC) to protect them from reaching excessive temperatures in hot engine environments. Acute angle TBC drilling brings three major simultaneous complications to the process. These are: (i) multi-layer drilling, (ii) non-symmetrical geometry and melt ejection, and (iii) increased depth of drilling. In a previous investigation by the authors, delamination of TBC was found as a main problem of angled drilling and mechanisms involved were studied. In the present study, implications of these difficulties on the hole quality is investigated through a comparative study of vertical and acute angle drilled holes. Characteristics of recast layer, heat-affected zone (HAZ), oxide layer and TBC delamination are investigated. Variation of these metallurgical characteristics with the depth of the hole is evaluated. Results for vertical and inclined holes are compared. The extent of HAZ, recast layer and oxide layer is seen to vary significantly with location and is found increasing with decreasing drilling angle to surface. Numerical simulation of pulsed laser heating of TBC Nimonic 263 was carried out for acute angle drilling with assist gas considerations. Results from the simulation suggested that the total heat transfer rate is higher on the leading edge side than the trailing edge of the heated region. Experimentally observed larger HAZ on leading edge side and larger recast layer on trailing edge side are explained by the analysis of heat flow characteristics obtained with the model. {\textcopyright} 2006 Elsevier Ltd. All rights reserved.",

keywords = "Heat affected zone, Laser drilling, Recast layer, Thermal barrier coating",

author = "Sezer, {H. K.} and L. Li and M. Schmidt and Pinkerton, {A. J.} and B. Anderson and P. Williams",

year = "2006",

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language = "English",

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T1 - Effect of beam angle on HAZ, recast and oxide layer characteristics in laser drilling of TBC nickel superalloys

AU - Sezer, H. K.

AU - Li, L.

AU - Schmidt, M.

AU - Pinkerton, A. J.

AU - Anderson, B.

AU - Williams, P.

PY - 2006/12

Y1 - 2006/12

N2 - Industrial applications of laser drilling include the production of cooling holes at acute angles in certain parts of the aero-engine components. These parts are often covered with ceramic thermal barrier coatings (TBC) to protect them from reaching excessive temperatures in hot engine environments. Acute angle TBC drilling brings three major simultaneous complications to the process. These are: (i) multi-layer drilling, (ii) non-symmetrical geometry and melt ejection, and (iii) increased depth of drilling. In a previous investigation by the authors, delamination of TBC was found as a main problem of angled drilling and mechanisms involved were studied. In the present study, implications of these difficulties on the hole quality is investigated through a comparative study of vertical and acute angle drilled holes. Characteristics of recast layer, heat-affected zone (HAZ), oxide layer and TBC delamination are investigated. Variation of these metallurgical characteristics with the depth of the hole is evaluated. Results for vertical and inclined holes are compared. The extent of HAZ, recast layer and oxide layer is seen to vary significantly with location and is found increasing with decreasing drilling angle to surface. Numerical simulation of pulsed laser heating of TBC Nimonic 263 was carried out for acute angle drilling with assist gas considerations. Results from the simulation suggested that the total heat transfer rate is higher on the leading edge side than the trailing edge of the heated region. Experimentally observed larger HAZ on leading edge side and larger recast layer on trailing edge side are explained by the analysis of heat flow characteristics obtained with the model. © 2006 Elsevier Ltd. All rights reserved.

AB - Industrial applications of laser drilling include the production of cooling holes at acute angles in certain parts of the aero-engine components. These parts are often covered with ceramic thermal barrier coatings (TBC) to protect them from reaching excessive temperatures in hot engine environments. Acute angle TBC drilling brings three major simultaneous complications to the process. These are: (i) multi-layer drilling, (ii) non-symmetrical geometry and melt ejection, and (iii) increased depth of drilling. In a previous investigation by the authors, delamination of TBC was found as a main problem of angled drilling and mechanisms involved were studied. In the present study, implications of these difficulties on the hole quality is investigated through a comparative study of vertical and acute angle drilled holes. Characteristics of recast layer, heat-affected zone (HAZ), oxide layer and TBC delamination are investigated. Variation of these metallurgical characteristics with the depth of the hole is evaluated. Results for vertical and inclined holes are compared. The extent of HAZ, recast layer and oxide layer is seen to vary significantly with location and is found increasing with decreasing drilling angle to surface. Numerical simulation of pulsed laser heating of TBC Nimonic 263 was carried out for acute angle drilling with assist gas considerations. Results from the simulation suggested that the total heat transfer rate is higher on the leading edge side than the trailing edge of the heated region. Experimentally observed larger HAZ on leading edge side and larger recast layer on trailing edge side are explained by the analysis of heat flow characteristics obtained with the model. © 2006 Elsevier Ltd. All rights reserved.

KW - Heat affected zone

KW - Laser drilling

KW - Recast layer

KW - Thermal barrier coating

U2 - 10.1016/j.ijmachtools.2006.01.010

DO - 10.1016/j.ijmachtools.2006.01.010

M3 - Article

SN - 0890-6955

VL - 46

SP - 1972

EP - 1982

JO - International Journal of Machine Tools and Manufacture

JF - International Journal of Machine Tools and Manufacture

IS - 15

ER -

Effect of beam angle on HAZ, recast and oxide layer characteristics in laser drilling of TBC nickel superalloys

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Keywords

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LPRC: Laser Processing Research Centre Impact

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