用正电子湮没技术研究深低温下Al—Li—Cu—Mg—Zr合金中的缺陷和电子密度

PAT study of defect and electron density in Al-Li-Cu-Mg-Zr alloy under cryogenic temperature

测量了欠时效和峰值时效的Ａｌ—Ｌｉ—Ｃｕ—Ｍｇ－Ｚｒ合金从深低温到室温升温过程的正电子湮没寿命谱．对ｅ＋寿命谱特征参数的分析表明．两种样品中的缺陷在升温过程中的运动规律是相似的。但峰值时效样品比欠时效样品回复缺陷的量更多；缺陷的平均开空间更大．而且随着δ＇（Ａｌ３Ｌｉ）相粒子的长大，样品基体中自由电子密度提高，增加了合金基体的强度．

The positron annihilation lifetime spectra of the under-aged and peak-aged Al-Li-Cu-Mg-Zr alloys were measured in the range from cryogenic to room temperature. The positron annihilation lifetime spectra show that the defect behaviours between two samples in the whole process of temperature rising are similar, but amount of the recovered vacancies is much greater in the peak-aged sample than in the under-aged one, and the average open space of defects in the peak-aged one is larger. With the particle δ'(Al3Li) growing in aging, the bulk election density in the alloy is increased and the strength enhanced.