钛氚化物中氦迁移能的第一原理研究

First-principles Study of the Migration Energy of Helium in Titanium Ditride

应用第一原理方法研究了时效初期氦原子在理想的钛氚化物(TiT2)中的迁移行为。计算结果显示氦的迁移能是1.07eV,比氦自身的反冲能(1.03eV)大,因此氦原子很难迁移,从而很好地解释了氦在时效初期不溢出氚化物以及时效后期金属氚化物中出现氦泡的实验现象。以迁移能为基础建立的固氦标准比以位置择优取向能为基础建立的固氦标准更合理。

The migration behavior of Helium in ideal titanium ditritide （TiT2） is studied by first-principles method in this paper. It is showed that that the migration energy for helium is 1.07 eV, larger than the bounce energy of helium （1.03 eV）, making the migration of helium very difficult. This result explains why helium does not diffuse from tritides at the early stage of aging and the occurrence of helium bubbles in the metal tritides at the later aging stage. Compared with site-preferring energy based stabilizing-helium standard, the migration energy based stabilizing-helium standard will be more reasonable.