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模拟核芯FCM燃料的振荡烧结行为研究OA北大核心CSTPCD

Sintering Behavior of Simulating Core FCM Fuel via Hot Oscillatory Pressing

中文摘要英文摘要

全陶瓷微封装弥散(FCM)燃料以其较好的固有安全性而成为核能领域研究的重点.针对SiC基体难以烧结的问题,本研究利用振荡烧结具有加速传质和降低烧结温度的优势,开展了模拟核芯FCM燃料振荡烧结行为研究,重点考察了振荡烧结温度、振荡时间与振荡压力等参数对基体致密化行为的影响,并与热压烧结结果进行了对比.结果表明,振荡烧结温度、保温时间以及中值压力对基体致密化有重要影响,而振荡压力的振幅对基体致密化影响不大.相比于热压烧结,振荡烧结可以提高材料的致密度,振荡烧结试样的致密度更高,1850 ℃振荡烧结试样的致密度为99.99%;振荡烧结试样的晶粒尺寸更小,1850 ℃振荡烧结试样的晶粒尺寸为(284±4)nm,比同等温度下热压烧结试样的晶粒尺寸减小~27%;振荡烧结试样的硬度更高,1850 ℃振荡烧结试样的硬度为(26.7±0.4)GPa.借助改进的热压烧结本构方程,计算得到试样在致密度为90%时的应力指数n=1,活化能Q=430 kJ/mol,致密化的主导机制为晶界扩散协调的晶界滑移.

Fully ceramic micro-encapsulated(FCM)fuel has become the focus of nuclear energy research because of its good inherent safety.In order to overcome the difficulty of SiC matrix densification,this study focused on the sintering behavior of simulating core FCM fuel via hot oscillatory pressing(HOP),taking the advantages of HOP to accelerate mass transfer and reduce sintering temperature.The influence of oscillatory sintering temperature,oscillatory time and oscillatory pressure on the matrix densification behavior was studied,and the results were compared with those of hot pressing(HP).The results indicate that the oscillatory sintering temperature,holding time,and median pressure have important effects on matrix densification,while the amplitude of oscillatory pressure has little effect.Compared with HP,the density of the samples is increased by HOP,and the density of sample sintered at 1850 ℃ via HOP is 99.99%.The grain size of the samples via HOP is smaller,and the grain size of the sample sintered via HOP at 1850 ℃ is(284±4)nm,which is~27%less than that of the sample sintered via HP at the same temperature.The hardness of the samples sintered via HOP is higher,and the hardness of the sample sintered via HOP at 1850 ℃ is(26.7±0.4)GPa.When the density of sample is 90%,the stress exponent n=1 and activation energyQ=430 kJ/mol are obtained by using the modified constitutive equation of HP.The dominant mechanism of densification is grain boundary sliding,which is accommodated by the grain boundary diffusion.

何宗倍;陈放;刘佃光;李统业;曾强

中国核动力研究设计院核燃料元件及材料研究所,成都 610213西南交通大学材料科学与工程学院,成都 610031

核科学

FCM燃料SiC基体振荡烧结致密化机理

fully ceramic micro-encapsulated fuelSiC matrixhot oscillatory pressingdensification mechanism

《无机材料学报》 2024 (005)

501-508 / 8

装备预研重点实验室基金项目(6142A06200108);中核集团基础研究项目(CNNC-JCYJ-202218)National Defense Key Laboratory Foundation(6142A06200108);China National Nuclear Corporation Basic Research Foundation(CNNC-JCYJ-202218)

10.15541/jim20230492

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