Microstructural observations of as-prepared and thermal cycled NiCoCrAlY bond coats

被引：41

作者：

Mendis, B. G.

Tryon, B.

Pollock, T. M.

Hemker, K. J. ^{[1
]}

机构：

[1] Johns Hopkins Univ, Dept Mech Engn, Baltimore, MD USA

[2] Univ Michigan, Dept Mat Sci, Ann Arbor, MI 48109 USA

来源：

SURFACE & COATINGS TECHNOLOGY | 2006年 / 201卷 / 07期

关键词：

NiCoCrAlY bond coat; phase transitions; diffusion; transmission electron microscopy;

D O I：

10.1016/j.surfcoat.2006.07.249

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

Microstructures of as-prepared and 1100 degrees C/100 h isothermally annealed NiCoCrAlY bond coat specimens as well as a bond coat obtained from an end of life turbine blade were characterized with TEM. In all specimens the gamma grains were observed to consist of fine gamma precipitates, which form during cooling and are unstable at the higher operating temperatures. The beta grains present in the as-prepared specimens were observed to transform to L1(0) martensite in the 1100 degrees C/100 h isothermally annealed specimen. As a result of substrate-bond coat interdiffusion the M-s temperature increases during thermal cycling due to an increase in Ni and decrease in the Cr concentrations of the beta-phase. The turbine blade bond coat was also found to contain Cr and Co-rich sigma-phase precipitates. (c) 2006 Elsevier B.V All rights reserved.

引用

页码：3918 / 3925

页数：8

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