Depth profiles of defects in Ar-iondashirradiated steels determined by a least-squares fit of S parameters from variable-energy positron annihilation
Depth profiles of defects in Ar-iondashirradiated steels determined by a least-squares fit of S parameters from variable-energy positron annihilation
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DOI：
10.1016/0169-4332(94)00336-x
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发表时间：
1995-01
影响因子：
6.7
通讯作者：
T. Aruga;S. Takamura;K. Nakata;Y. Ito
中科院分区：
文献类型：
--
作者：
T. Aruga;S. Takamura;K. Nakata;Y. Ito
用一种用慢正电子重建电离辐照样品中缺陷深度分布的新方法，由测量到16keV正电子能量的多普勒展宽S参数，计算了室温下250keV Ar离子辐照剂量为7.5×1019m−_2的316不锈钢样品中空位型缺陷的深度分布。在不假设缺陷轮廓的任何类型的形状(如高斯)的情况下，使用最小二乘拟合方法来完成缺陷轮廓。结果表明，在碳含量较低的辐照316不锈钢样品中，缺陷分布峰位于比离子范围深四倍的深度处。在1253K高温下热处理0.5h后，拟合的轮廓显示平均离子射程附近的峰大大增强。而在添加0.3wt%钛的钢中，在1073K下退火后，轮廓几乎没有峰。结果表明，注入的Ar原子比添加钛的钢更有效地稳定了辐照产生的空位团。
Using a new method for reconstructing the depth profile of defects in an iondashirradiated sample by using slow positrons, the depth profiles of vacancy-type defects in 316 stainless steel samples, irradiated with 250 keV Ar ions to a dose of 7.5 × 1019m−2at room temperature, have been calculated from Doppler-broadening S parameters measured as a function of positron energies up to 16 keV. Without assuming any type of shape for the defect profiles, such as Gaussian, the defect profiling is done using a least-squares fitting method. The resulting profile suggests that in as-irradiated 316 stainless steel samples with lower carbon content, the defect distribution peaks at a depth four times larger than that of the ion range. After annealing at a high temperature of 1253 K for 0.5 h, the fitted profile shows that the peak around the average ion range is highly enhanced. While in the steel added with 0.3 wt% titanium, the profile exhibits almost no peak after annealing at 1073 K. The results indicate that the radiationdashproduced vacancy clusters are stabilized by the implanted Ar atoms more effectively in the Ti-free steel than in the Ti-added steel.