Interstitial Helium Diffusion in Metals

金属中的间隙氦扩散

• 批准号: 01460214
• 负责人: HASHIMOTO Eiji
• 金额: $ 2.18万
• 依托单位: Hiroshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01460214/
• 关键词: Helium in Metals; Diffusion in Solids; Thermal- Desorption Method; Interstitial Atlm; Ion Irradiation; 拡散; ガス透過法

In order to get information about the diffusion of interstitial helium in metals. Measurements have been made on the thermal desorption of helium from high purity aluminum irradiated with 19 keV He ions. The irradiation was performed at room temperature up to 1 x 10^<15> - 5 x 10^<16> He^+cm^<-2>.Remarkable features of the results are as follows. (1) Almost all helium atoms implanted are released released during heating up to the melting point or more. (2) A rapid helium evolution occurs just below the melting point, irrespective of irradiation dose. (3) For irradiation more than 5 x 10^<15> He^+cm^<-2>, another evolution rate peak appears ; the peak area is increased markedly with increasing irradiation dose, while the peak position is shifted to the lowler temperature side. In particular, the result (3) suggests that the evolution peak appearing in the lower temperature region may be due to diffusion and evolution of helium emitted spontaneously from small cavities containing a large number of helium atoms. According to the above, the activation energy for the helium evolution in the lower temperature region (100-200 ^ﾟC) was estimated from the desorption rates before and after the abrupt temperature chane during stepwise heating. The value obtained is about 0.3 eV. This value is very close to thouse (0.2-0.3 eV) calculated for interstitial helium diffusion in aluminum.

为了得到氦在金属中扩散的信息。用19kev He离子辐照高纯铝，对氦的热解吸进行了测量。在室温下辐照至1 × 10^<15> - 5 × 10^<16> He^+cm^<-2>。结果的显著特征如下。几乎所有注入的氦原子都在加热到熔点以上时释放出来。(2)与辐照剂量无关，氦在熔点以下发生快速析出。(3)当辐照量大于5 × 10^<15> He^+cm^<-2>时，出现另一个演化速率峰；随着辐照剂量的增加，峰值面积明显增大，峰值位置向温度较低的一侧偏移。特别是(3)的结果表明，出现在低温区的演化峰可能是由于氦从含有大量氦原子的小腔中自发发射的扩散和演化。由此，通过逐级加热过程中温度突变前后的解吸速率估算出低温区（100 ~ 200 ^ C）氦演化的活化能。得到的值约为0.3 eV。这一数值与氦在铝中的间隙扩散计算值（0.2-0.3 eV）非常接近。