Phase evolution and mechanical properties of novel nanocrystalline Y_(2)(TiZrHfMoV)_(2)O_(7) high entropy pyrochlore  

作　　者：G.Karthick Lavanya Raman B.S.Murty 

机构地区：[1]Department of Metallurgical and Materials Engineering,Indian Institute of Technology Madras,Chennai,600036,India [2]Indian Institute of Technology Hyderabad,Kandi,502285,India

出　　处：《Journal of Materials Science & Technology》2021年第23期214-226,共13页材料科学技术（英文版）

摘　　要：High entropy pyrochlores(HEP)are potential candidates as dispersoids in the oxide dispersed strengthened steels or alloys,which can be used in nuclear reactors and supercritical boilers.For the first time,HEP oxides Y_(2)(TiZrHfMoV)_(2)O_(7) were synthesized with Y_(2)Ti_(2)O_(7) as a base structure with the B site(Ti)substituted with five cations through reverse co-precipitation technique in the nanocrystalline form at lowest synthesis temperature.The synthesis parameters for Y_(2)(TiZrHfMoV)_(2)O_(7)(5C)and other derived compositions(five compositions of four cationic systems with each cation eliminated at B site from 5 C)are optimised to obtain lower crystallite and particle sizes.5C has a smaller crystallite size(27 nm)than other single-phase compositions.The cation’s influence,oxidation state,and oxygen vacancy in the phase formation were analysed through XPS.The single-phase HEPs are consolidated through spark plasma sintering.Y_(2)(TiZrHfMo)_(2)O_(7)(4 C-V)shows the highest hardness among the compositions reported so far due to its finer grain size,and Y_(2)(TiHfMoV)_(2)O_(7)(4 C-Zr)has a higher Young’s modulus compared to other single-phase composition due to its higher degree of order in the structure.

关 键 词：High entropy pyrochlores Reverse co-precipitation B site substitution Hardness Young’s modulus 

分 类 号：TG139[一般工业技术—材料科学与工程]