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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 composites are the best neutron absorbing materials at present, but there is a problem of poor interfacial wettability in the process of liquid mixing commonly used in industry. The interfacial wettability of B 4 C / Al interface was analyzed by combining the experiment and first principles with the structure of Al (111) / AlB_2 (0001) and Al (111) / TiB_2 Improvement mechanism. The results show that the interface between Al (111) / TiB_2 (0001) and Al (111) / AlB_2 (0001) has higher adhesion work value, indicating that the interface of Al (111) / TiB_2 Further comparison of the skewed density structures of Ti-doped diborides and AlB_2 reveals that the Ti-doped counterparts have a lower antibonding state, indicating that the Ti-3d and B-2p orbitals are electronly hybridized to form B and Ti atoms (111) / TiB_2 (0001) interface and improve the bonding strength of the Al (111) / TiB_2 (0001) interface, thus improving the adhesion of the B_4C / Al interface Wet. According to the same theoretical basis, the V-dopant also has a lower antibond state. The strong bonding effect between V and B may improve the wettability of the B 4 C / Al interface and become another ideal solution-modified doping element.