In-situ synthesis of high-entropy Al_(2)O_(3)/RE_(3)Al_(5)O_(12)/ZrO_(2)ceramic by laser powder bed fusion with exceptional properties  

作　　者：Zhiwei Xiong Kai Zhang Wenhe Liao Tingting Liu Yang Zhang Zhiguang Zhu 

机构地区：[1]School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China

出　　处：《Journal of Advanced Ceramics》2024年第12期2004-2020,共17页先进陶瓷(英文)

基　　金：supported by the National Natural Science Foundation of China(No.52005262);the National Key R&D Program of China(No.2022YFB4600800).

摘　　要：Eutectic ceramics with exceptional hardness,elevated Young’s modulus,and impressive fracture toughness have become indispensable materials for various demanding industrial applications in extreme environments.In this work,in-situ synthesis of high-entropy Al_(2)O_(3)/(Y_(0.2)Eu_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(3)Al_(5)O_(12)/ZrO_(2)ceramics was successfully achieved with onestep slurry-based laser powder bed fusion(LPBF).The phase formation,microstructure morphologies,phase distribution,crystallographic characteristics,and mechanical properties were systematically investigated.The typical microstructure of a shell–core architecture resembling cell-like features consists of both crystalline and amorphous phases.The selective aggregation of constituents is the combined outcome of solute exclusion and convective transport mechanisms.The crystallographic orientation relationships inside the shell may include■ZrO_(2)//RE_(3)Al_(5)O_(12)and RE_(3)Al_(5)O_(12)//ZrO_(2).During the rapid cooling of LPBF,the amorphous phase is an intermediate metastable product of crystal structure adjustment(REAlO_(3),RE_(4)Al_(2)O_(9)→amorphous phase→RE_(3)Al_(5)O_(12)).Owing to the slower diffusion rate and higher transition energy threshold of Eu elements,more Eu elements are retained in the amorphous phase.Structural analysis indicates that the remarkable mechanical properties can be attributed to several factors,including the significant dissociation energy,strong cationic field,and stress transfer among Al_(2)O_(3),RE_(3)Al_(5)O_(12),ZrO_(2),and the amorphous phase.Additionally,the cocktail effect and plastic deformation mechanism of the high-entropy shell contribute to these properties.

关 键 词：laser powder bed fusion(LPBF) Al_(2)O_(3)-RE_(3)Al_(5)O_(12)-ZrO_(2) high-entropy ceramic mechanical properties crystallographic characteristics 

分 类 号：TG1[金属学及工艺—金属学]