摘要
采用激光区熔定向凝固技术制备了Al2O3/YAG/ZrO2三元亚共晶自生复合陶瓷,研究了不同激光扫描速率下亚共晶自生复合陶瓷的微观组织,并与激光区熔定向凝固Al2O3/YAG二元及Al2O3/YAG/ZrO2三元共晶自生复合陶瓷的微观组织进行了对比。结果表明,激光区熔定向凝固Al2O3/YAG/ZrO2三元亚共晶由相互交错分布的α-Al2O3、YAG和c-ZrO2三相组成,无其它结晶相和无定形相;随激光扫描速率的增大,凝固组织发生显著变化,出现了由共晶集群到较为规则的树枝状共晶再到杂乱的树枝状共晶的组织转变。初生相的枝晶生长,使得亚共晶陶瓷的凝固组织明显不同于共晶陶瓷的凝固组织;亚共晶凝固组织呈现典型的小平面非规则共晶形貌,凝固组织主要由Al2O3和YAG两相的小平面生长方式决定,第三组元ZrO2相表现出弱小平面生长特征。
In-situ synthesized Al2O3/YAG/ZrO2 hypoeutectic ceramic composites are prepared by laser zone melting directional solidification technique. The solidification microstructure of hypoeutectic ceramics with different laser scanning rate was studied and was compared with those of Al2O3/YAG binary and Al2O3/YAG/ZrO2 ternary eutectic ceramics. The results show that. （1） The directionally solidified Al2O3/YAG/ZrO2 hypoeutectic consists of α-Al2O3, YAG and c-ZrO2 interpenetrating with each other without other crystalline and amorphous phases; （2） With increasing laser scanning rate, the microstructure changes significantly from eutectic colony to relatively regular dendrite and then to disordered dendrite. The solidified microstructure of hypoeutectic ceramic is quite different from that of eutectic ceramic due to the dendrite growth of primary phase; （3） The solidification microstructure of hypoeutectic ceramic has the irregularly faceted morphology which is mainly determined by the faceted growth of Al2O3 and YAG, while ZrO2 phase presents weak-faceted growth manner.
出处
《铸造技术》
CAS
北大核心
2009年第5期606-609,共4页
Foundry Technology
基金
国家自然科学基金(50772090)
航空基础科学基金(04G53048)
西北工业大学基础研究基金(NPU-FFR-W018101)
新金属材料国家重点实验室开放基金(2007AMM004)
