Grain boundary segregation induced strong UHTCs at elevated temperatures:A universal mechanism from conventional UHTCs to high entropy UHTCs

作     者：Fu-Zhi Dai Bo Wen Yinjie Sun Yixiao Ren Huimin Xiang Yanchun Zhou Fu-Zhi Dai;Bo Wen;Yinjie Sun;Yixiao Ren;Huimin Xiang;Yanchun Zhou

作者机构：Science and Technology on Advanced Functional Composite LaboratoryAerospace Research Institute of Materials&Processing TechnologyBeijing 100076China DP TechnologyBeijing 100044China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第123卷第28期

页      面：26-33页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(No.51672064) 

主　　题：UHTCs High entropy ceramics Grain boundary segregation High-temperature strength Machine learning potential 

摘      要：Ultra-high temperature ceramics(UHTCs)exhibit a unique combination of excellent properties,including ultra-high melting point,excellent chemical stability,and good oxidation resistance,which make them promising candidates for aerospace and nuclear ***,the degradation of hightemperature strength is one of the main limitations for their ultra-high temperature ***,searching for mechanisms that can help to develop high-performance UHTCs with good high-temperature mechanical properties is urgently *** achieve this goal,grain boundary segregation of a series of carbides,including conventional,medium entropy,and high entropy transition metal carbides,i.e.,Zr_(0.95)W_(0.05)C,TiZrHfC_(3),ZrHfNbTaC_(4),TiZrHfNbTaC_(5),were studied by atomistic simulations with a fitted Deep Potential(DP),and the effects of segregation on grain boundary strength were *** all the studied carbides,grain boundary segregations are realized,which are dominated by the atomic size *** addition,tensile simulations indicate that grain boundaries(GBs)will usually be strengthened due to *** simulation results reveal that grain boundary segregation may be a universal mechanism in enhancing the high-temperature strength of both conventional UHTCs and medium/high entropy UHTCs,since GBs play a key role in controlling the fracture of UHTCs at elevated temperatures.