Microstructural evolution and failure characteristics of a NiCoCrAlY bond coat in "hot spot" cyclic oxidation

被引：55

作者：

Cao, F. ^{[1
]}

Tryon, B. ^{[2
]}

Torbet, C. J. ^{[3
]}

Pollock, T. M. ^{[3
]}

机构：

[1] ExxonMobil Res & Engn Co, Annandale, NJ 08801 USA

[2] Pratt & Whitney, E Hartford, CT 06118 USA

[3] Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA

来源：

ACTA MATERIALIA | 2009年 / 57卷 / 13期

关键词：

Coating; Oxidation; Microstructure; Bond coat; Failure; THERMAL BARRIER COATINGS; GROWN OXIDE; MECHANISMS; DURABILITY; DEPOSITION; ALUMINIDE; PLATINUM; SYSTEMS; IMPERFECTIONS; SIMULATIONS;

D O I：

10.1016/j.actamat.2009.04.039

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Microstructural evolution and the onset of failure in a NiCoCrAlY bond coat (BC) on a single-crystal superalloy substrate have been investigated in a newly developed "hot spot" apparatus that imposes a temperature gradient along the length of a coated, cylindrical specimen. Local spallation events were observed in the "hottest spot" of the coated specimens after 50-60 oxidation cycles with a peak temperature of 1050 degrees C. The thickness of the thermally grown oxide (TGO) was in the range of 2-3 mu m when spalls were initiated. The failure surface contained a significant density of embedded oxides and the remanant TGO exhibited surface cracks indicative of a buckling delamination failure mode. The failed surface morphology and the cross-section microstructure of the BC have been characterized, including morphological imperfections in the TGO. The role of these microstructural features in the failure process is addressed. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：3885 / 3894

页数：10

共 40 条

[11] MECHANISMS OF FORMATION OF DIFFUSION ALUMINIDE COATINGS ON NICKEL-BASE SUPERALLOYS [J].