An approach of stand‑of measuring hardness of tungsten heavy alloys using LIBS
An approach of stand‑of measuring hardness of tungsten heavy alloys using LIBS
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一种利用LIBS远距离测量钨高合金硬度的方法
DOI：
10.1007/s00340-019-7355-0
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Hongbin Ding
中科院分区：
文献类型：
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作者：
Harse Sattar;Hai Ran;Wu Ding;Muhammad Imran;Muhammad Amir;Hongbin Ding
表面硬度和微观结构特性是面向等离子体材料的重要参数，在聚变反应堆的长脉冲运行中起着关键作用。如今，核反应堆面临着由于主导的极端条件而导致物理性能尤其是表面硬度变化的问题。因此，监控这些变化非常重要。激光诱导击穿光谱 (LIBS) 具有潜在的诊断能力，可以监测原位表面硬度及其与等离子体壁相互作用的相关性。在这项工作中，不同钨合金牌号的硬度是通过使用 LIBS 的隔离方法来测量的。硬度的差异归因于材料的晶粒尺寸、晶体尺寸、位错密度和能带隙(Eg)。这些微观结构和电子结构特性对激光烧蚀等离子体中的电子温度有直接影响。使用玻尔兹曼图方法确定了等离子体电子温度，范围为 1.76±0.01 至 1.90±0.02 eV，而电子密度则使用 (W-I) 429.47 nm 线的 Stark 展宽光谱剖面得出。所获得的离子与原子种类 (WII/WI) 和材料硬度之间的直接关系与等离子体电子温度 (Te) 值的增加有关。随着硬度从 314±±2.2 增加到 354±±1.1，这些钨重合金靶材的能带隙从 3.24 eV 增加到 3.59 eV。结果表明，这些靶材的能带隙随着硬度的增加而增大，并且与等离子体电子温度有直接关系。还根据凹坑深度分析测量了烧蚀效率作为激光辐照度的函数。结果表明，从软材料到硬材料，平均烧蚀率降低。
Surface hardness and microstructural properties are important parameters of plasma-facing material and play a key role in long pulse operation of fusion reactor. Nowadays, nuclear reactors are facing the problem of change in physical properties especially surface hardness due to dominant extreme conditions. Consequently, it is important to monitor these changes. Laser-induced breakdown spectroscopy (LIBS) has a potential diagnostic ability to monitor in situ surface hardness and their correlation with plasma wall interaction. In this work, the hardness of different tungsten heavy alloy grades is measured by stand-off approach using LIBS. The difference in hardness was attributed to grain size, crystal size, dislocations density and energy band gap (Eg) of materials. These microstructural and electronic structure properties have direct impact on electron temperature in laser-ablated plasma. Plasma electron temperature has been determined using Boltzmann plot method in the range from 1.76 ± 0.01 to 1.90 ± 0.02 eV, while electron density has been derived using Stark broadening spectral profile of (W-I) 429.47 nm line. The obtained direct relation between the ionic to atomic species of (WII/WI) and the material hardness are associated to increase in the value of plasma electron temperature (Te). The energy band gap of these tungsten heavy alloy targets has been observed from 3.24 to 3.59 eV as hardness increases from 314 ± 2.2 to 354 ± 1.1. The results showed that the energy band gap of these targets increases with hardness and have direct relation with plasma electron temperature. Ablation efficiency was also measured as a function of laser irradiance from crater depth analysis. The results showed that average ablation rate is decreased from soft to hard material.