In this paper, the NiCrAlYSi coatings are deposited by electron beam physical vapor deposition (EB-PVD) on nickel-based single crystal superalloy DD6. Inter-diffusion and recrystallization behaviors at the coating/superalloy interface of the coated superalloy substrates are investigated at 1 323 K by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS) and transmission electron microscopy (TEM). The results indicate that a recrystallization zone of ~7 μm thickness is formed at the coating/substrate interface of the blasted sample after 4 h vacuum heat-treatment at 1 323 K. Such recrystallization zone is not observed in the unblasted sample even after 50 h heat-treatment. However, a recrystallization zone of ~15 μm thickness is formed in the sample after 75 h. After 500 h isothermal oxidation in air at 1 323 K, a recrystallization zone of ~28 μm thickness is formed in the unblasted sample. Besides, a so-called secondary reaction zone of ~60 μm, basically consisting of topologically close-packed phase (TCP) needles, is formed in the superalloy. The precipitate of TCP is enriched in W, Re and Ta.
YAO Rui, GUO Hongbo, PENG Hui, GONG Shengkai
. Recrystallization and Inter-diffusion Behaviors of NiCrAlYSi Coating/DD6 Single Crystal Superalloy System[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2011
, 32(4)
: 751
-757
.
DOI: CNKI:11-1929/V_20101028.1820.001
[1] Padture N P, Gell M, Jordan E H. Thermal barrier coatings for gas-turbine engine applications[J]. Science, 2002, 296(5566): 280-284.
[2] Sohn Y H, Lee E Y, Nagaraj B A, et al. Microstructural characterization of thermal barrier coatings on high pressure turbine blades[J]. Surface and Coatings Technology, 2001, 146-147: 132-139.
[3] Hesnawi A, Li H F, Zhou Z H, et al. Isothermal oxidation behavior of EB-PVD MCrAlY bond coat[J]. Vacuum, 2007, 81(8): 947-952.
[4] 杨苹丽. 电弧离子镀NiCoCrAlY(SiB)涂层的组织结构及性能研究. 吉林:吉林大学,2006. Yang Pingli. Microstructure of AIP NiCoCrAlY(SiB) coatings. . Jilin: Jilin University, 2006. (in Chinese)
[5] Wu Y N, Wang Q M, Ke P L, et al. Evaluation of arc ion plated NiCoCrAlYSiB coatings after oxidation at 900-1 100 ℃ [J]. Surface and Coatings Technology, 2006, 200(9): 2857-2863.
[6] Walston W S, Schaeffer J C, Murphy W H. A new type of microstructural instability in superalloys—SRZ//Proceedings of the Eighth International Symposium on Superalloy. 1996: 9-18.
[7] Matsuoka Y, Aoki A, Matsumoto K, et al. The formation of SRZ on a fourth generation single crystal superalloy applied with aluminide coating //Proceedings of Superalloys 2004. 2004: 637-642.
[8] Brandl W, Grabke H J, Toma D, et al. The oxidation behavior of sprayed MCrAlY coatings [J]. Surface and Coatings Technology, 1996, 86-87(1): 41-47.
[9] Choi H, Yoon B, Kim H, et al. Isothermal oxidation of air plasma spray NiCrAlY bond coatings [J]. Surface and Coatings Technology, 2002, 150(2-3): 297-308.
[10] Czech N, Schmitz F, Stamm W. Microstructural analysis of the role of rhenium in advanced MCrAlY coatings[J]. Surface and Coatings Technology, 1995, 76-77(1): 28-33.
[11] Beele W, Czech N, Quadakkers W J, et al. Long-term oxidation tests on a Re-containing MCrAlY coatings[J]. Surface and Coatings Technology, 1997, 94-95: 41-45.
[12] Narita T, Yoshida D. Heat-resistant nickel-alloy composite excellent in high temperature oxidation resistance: US Patent 7285337. 2007-10-23.
[13] Xu C Z, Jiang S M, Bao Z B, et al. Isothermal oxidation behavior of a gradient NiCoCrAlSiY coating deposited by arc ion plating on a Ni-based single crystal superalloy[J]. Corrosion Science, 2009, 51(6): 1467-1474.
[14] Nystrom J D, Pollock T M, Murphy W H, et al. Discontinuous cellular precipitation in a high-refractory nickel-base superalloy[J]. Metallurgical and Materials Transactions A, 1997, 28(12): 2443-2452.
[15] 刘刚, 刘林, 赵新宝, 等. 难熔元素对镍基单晶高温合金凝固特性及组织的影响[J]. 材料导报, 2008, 22(9): 38-42. Liu Gang, Liu Lin, Zhao Xinbao, et al. Influence of re-fractory elements addition on solidification characteristics and microstructure of Ni-based single-crystal superalloys[J]. Materials Review, 2008, 22(9): 38-42. (in Chinese)
[16] Peng H, Guo H B, He J, et al. Cyclic oxidation and diffusion barrier behaviors of oxides dispersed NiCoCrAlY coatings[J]. Journal of Alloys and Compounds, 2010, 502(2): 411-416.
CJA