Microstructure of Al2O3 nanocrystalline/cobalt-based alloy composite coatings by laser deposition

被引：27

作者：

Li, Mingxi ^{[1
]}

He, Yizhu ^{[1
]}

Yuan, Xiaomin ^{[1
]}

Zhang, Shillong ^{[1
]}

机构：

[1] Anhui Univ Technol, Sch Mat Engn, Res Ctr Laser Proc, Maanshan 243002, Peoples R China

来源：

MATERIALS & DESIGN | 2006年 / 27卷 / 10期

关键词：

laser deposition; Al2O3; nanocrystalline; cobalt-based alloy; equiaxed crystallization; microstructure;

D O I：

10.1016/j.matdes.2005.03.018

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Composite coatings, made of nano-Al2O3/cobalt-based alloy, produced by a 5-kW CO2 laser on Ni-based superalloy were investigated. The coatings were examined to reveal their microstructure using optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffraction instrument. The results showed that some equilibrium or non-equilibrium phases, such as gamma-Co, Cr23C6, CoAl2O4, Al2O3 and epsilon-Co existed in the coatings. Fine and short dendritic microstructure and columnar to equiaxed transition occurred by adding nano-Al2O3 particle. With the increase of nano-materials (1%, mass fraction), fully equiaxed crystallization appeared. These were contributed to that nano-Al2O3 particles acted as new nucleation site and rapid solidification of the melted pool. The results also showed inhomogeneous dispersion of nano-Al2O3 that resulted in the formation of epsilon-Co phase in the coatings. The sub-micro structure of the clad was stacking fault. The mechanism of formation of equiaxed grains was also analyzed. (C) 2005 Elsevier Ltd. All rights reserved.

引用

页码：1114 / 1119

页数：6

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