Microstructure tailoring and thermal stability of directionally solidified Al2O3/GdAlO3 binary eutectic ceramics by laser floating zone melting

被引：17

作者：

Su, Haijun ^{[1
]}

Wang, Enyuan ^{[1
]}

Ren, Qun ^{[1
]}

Liu, Haifang ^{[1
]}

Zhao, Di ^{[1
]}

Fan, Guangyao ^{[1
]}

Zhang, Jun ^{[1
]}

Liu, Lin ^{[1
]}

Fu, Hengzhi ^{[1
]}

机构：

[1] Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Shaanxi, Peoples R China

来源：

CERAMICS INTERNATIONAL | 2018年 / 44卷 / 07期

基金：

中国国家自然科学基金; 国家重点研发计划;

关键词：

Eutectic ceramics; Oxide Ceramics; Directional solidification; Microstructure tailoring; Thermal stability; HIGH-TEMPERATURE STRENGTH; LIQUID INTERFACE MORPHOLOGY; MECHANICAL-PROPERTIES; CREEP-BEHAVIOR; ELEVATED-TEMPERATURES; CRYSTAL-GROWTH; 1900; K; COMPOSITE; STRIATIONS; LAMELLAR;

D O I：

10.1016/j.ceramint.2018.01.228

中图分类号：

TQ174 [陶瓷工业]; TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

Directionally solidified Al2O3/GdAlO3 eutectic composite ceramics with low solidification defects are prepared by laser floating zone melting to tailor homogeneous microstructure and thermal stability performance under high temperature gradient. At low solidification rate, the solidification microstructure shows periodical growth striations in which coarse colony microstructure and homogeneous 'Chinese script' irregular eutectic structure are coexisted. The growth striation interval L and solidification rate V follow the relationship of L/V = (238.8 +/- 2.4) s. By further optimizing laser processing parameters, the eutectic spacing is greatly refined to submicron scale and microstructure oscillation is eliminated at high solidification rates, and fully regular lamellar/rod eutectic structures are obtained by faceted eutectic transition. The rod-like eutectic spacing (lambda) and solidification rate (V) follow the linear relationship of lambda.V-1/2 = 6.21 mu m(3/2) s(-1/2). Furthermore, the as-solidified eutectic composite even with fine eutectic structure exhibits excellent thermal stability after heat exposure at 1500 degrees C for 250 h.

引用

页码：7908 / 7916

页数：9

共 50 条

[1] SHAPE INSTABILITIES OF EUTECTIC COMPOSITES AT ELEVATED TEMPERATURES [J].