摘要
B_4C/Al复合材料是目前最理想的中子吸收材料,但工业上常用的液态搅拌法制备过程中存在着界面润湿性差的问题。结合实验及第一性原理的方法,通过研究Al(111)/AlB_2(0001)和Al(111)/TiB_2(0001)界面的结构来分析工业上添加过渡元素Ti对B_4C/Al界面润湿性的改善机制。通过计算发现,Al(111)/TiB_2(0001)界面相对Al(111)/AlB_2(0001)界面具有更高的粘附功值,说明其界面结合更强。进一步对比Ti掺杂二硼化物和AlB_2的偏态密度结构,发现Ti掺杂体具有较低的反键态,表明Ti-3d和B-2p轨道电子杂化后,在B、Ti原子间形成了较强的化学键,从而促进了Al(111)/TiB_2(0001)界面处的强结合作用,提高了Al(111)/TiB_2(0001)界面粘附功,故而改善了B_4C/Al界面的润湿性。根据同样的理论依据,V掺杂体也具有较低的反键态,V和B之间的强结合效果或许能够改善B_4C/Al界面的润湿性,成为又一理想的溶体改性掺杂元素。
B_4C/Al MMC is one of the most potential neutron-shielding materials. The poor wettability of B_4C/Al interface damages the mechanical properties. To understand the alloying(or doping) effects in improving the wettability of B_4C/Al interfaces,we investigated the Al(111)/AlB_2(0001) and Al(111)/TiB_2(0001) interfacial structures via a combined approach of experiment and DFT calculations. We find a larger work of adhesion(Wad) on the Al(111)/TiB_2(0001) than the Al(111)/AlB_2(0001) interfaces. The subsequently calculated partial density of states(PDOS) of doped-diborides show fewer anti-bonding states in Al(111)/TiB_2(0001) than in Al(111)/AlB_2(0001),which contribute to a stronger bonding between Ti-3d and B-2p states and lead to a higher Wad and better wetting. Furthermore,we predict improved wettability of Al/B4 C by V-doping,because of the fewer anti-bonding states in vanadium-boron molecular orbitals. The same approach developed in this study may be applied for general design of alloy elements to improve the interfacial wetting of alloy-semiconductor systems.
作者
王治璇
李丘林
郑继云
刘伟
束国刚
吴平
徐贲
Wang Zhixuan Xu BenI Li Qiulin Zheng Jiyun Liu Wei Shu Guogang Wu Ping Xu Ben(Tsinghua University, Beijing 100084, China Tsinghua University Graduate School, Tsinghua University City Park, Shenzhen 518055, China China Nuclear Power Engineering Co., Ltd, Technology Building, Shenzhen 518055, China Singapore University of Technology and De- sign, Singapore 487372, Singapore)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第9期2345-2351,共7页
Rare Metal Materials and Engineering
基金
National Natural Science Foundation of China(51301094)