Grain growth of nanocrystalline 3C-SiC under Au ion irradiation at elevated temperatures
Grain growth of nanocrystalline 3C-SiC under Au ion irradiation at elevated temperatures
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DOI：
10.1088/0022-3727/49/3/035304
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发表时间：
2016-01
期刊：
影响因子：
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通讯作者：
Limin Zhang;Weilin Jiang;A. Dissanayake;T. Varga;Jiandong Zhang;Zihua Zhu;Dehong Hu;Haiyan Wang;C. Henager;Tieshan Wang
中科院分区：
文献类型：
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作者：
Limin Zhang;Weilin Jiang;A. Dissanayake;T. Varga;Jiandong Zhang;Zihua Zhu;Dehong Hu;Haiyan Wang;C. Henager;Tieshan Wang
纳米碳化硅是研究核辐射下界面(晶界)过程的一个很好的模型体系，对于理解纳米结构材料对高剂量辐射的响应是至关重要的。本文比较了在700K等剂量的Au离子辐照下，几纳米尺寸的立方相碳化硅(3C-SiC)和单晶3C-碳化硅薄膜的辐照效应。与未完全非晶化的晶格无序积累到饱和水平的单晶碳化硅薄膜不同，前者的平均晶粒度随剂量呈幂函数增长趋势。除了聚结，颗粒还通过原子跳跃和质量传输来生长，在这些过程中，辐射诱导的晶界空位有助于这一过程。结果表明，辐照温度越高，晶粒长大速度越慢，达到饱和尺寸的速度越快。这一反常行为可能与辐照诱导非晶态碳化硅中的颗粒形核和长大有关，其中嵌入了3C-碳化硅颗粒。这一结果可能会对先进核能系统的结构组件产生积极影响。
Nanocrystalline silicon carbide (SiC) represents an excellent model system for a fundamental study of interfacial (grain boundary) processes under nuclear radiation, which are critical to the understanding of the response of nanostructured materials to high-dose irradiation. This study reports on a comparison of irradiation effects in cubic phase SiC (3C-SiC) grains of a few nanometres in size and single-crystal 3C-SiC films under identical Au ion irradiation to a range of doses at 700 K. In contrast to the latter, in which the lattice disorder is accumulated to a saturation level without full amorphization, the average grain size of the former increases with dose following a power-law trend. In addition to coalescence, the grain grows through atomic jumps and mass transport, where irradiation-induced vacancies at grain boundaries assist the processes. It is found that a higher irradiation temperature leads to slower grain growth and a faster approach to a saturation size of SiC nanograins. This unusual behaviour could be associated with irradiation-induced grain nucleation and growth in amorphous SiC matrix in which the 3C-SiC grains are embedded. The results could potentially have a positive impact on structural components of advanced nuclear energy systems.