Phase growth patterns for Al_(2)O_(3)/GdAlO_(3)eutectics over wide ranges of compositions and solidification rates  

作　　者：Weidan Ma Jun Zhang Haijun Su Guangrao Fan Min Guo Lin Liu Hengzhi Fu 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China

出　　处：《Journal of Materials Science & Technology》2021年第6期89-98,共10页材料科学技术（英文版）

基　　金：supported financially by the National Natural Science Foundation of China(Nos.51822405 and 51472200);the National Key R&D Program of China(Nos.2017YFB1103500 and2018YFB1106600);the Science,Technology and Innovation Commission of Shenzhen Municipality(No.JCYJ20180306171121424);the Research Fund of Equipment Development Department(No.61409230402);the Aeronautics Power Foundation(No.6141B09050337);the Innovation Fund of the Zhejiang Kechuang New Materials Research Institute(No.ZKN-18-P04);the Key R&D Program of Shaan Xi Province(No.2018ZDCXL-GY-09-04);the Research Fund of the State Key Laboratory of Solidification Processing(NPU)(No.2019-QZ-02)。

摘　　要：Phase selection and growth characteristics of directionally solidified Al_(2)O_(3)/GdAlO_3(GAP)faceted eutectic ce ramics are investigated over wide ranges of compositions and solidification rates to explore the eutectic coupled zone.Through the obse rvation of the quenched solid-liquid interface,the competitive growth of primary faceted Al_(2)O_(3)phase,prima ry non-faceted GAP phase and Al_(2)O_(3)/GAP eutectic with diffe rent morphologies is detected.Microstructure transitions from wholly eutectic to primary Al_(2)O_(3)(GAP)dendrite plus eutectic and then to wholly eutectic are found in Al_(2)O_(3)-2 O mol%Gd_(2)O_(3)hypoeutectic(Al_(2)O_(3)-26 mol%Gd_(2)O_(3)hypereutectic)ceramics with the increase of solidification rate.The dendrite growth of faceted Al_(2)O_(3)and non-faceted GAP phases are well predicted by KGT model,which have introduced appro p riate dimensionless supersaturationΩto characterize the anisotropic growth of dendrites.Based on the maximum interface temperature criterion,the competitive growth of primary phase and eutectic is analyzed theoretically and the predicted coupled zone of Al_(2)O_(3)/GAP eutectic ceramics is in good agreement with the experimental results.Besides,the influence of microstructure with these different morphologies on the flexural strength of Al_(2)O_(3)/GAP eutectic ceramics is studied.

关 键 词：Directional solidification Competitive growth Flexural strength Laser floating zone melting 

分 类 号：TQ174.1[化学工程—陶瓷工业]