纳秒脉冲激光辐照金属玻璃表面结构形成机制

发布时间：2018-06-18 06:45

本文选题：激光辐照 + 金属玻璃　；参考：《稀有金属》2017年10期

【摘要】：脉冲纳秒激光辐照金属玻璃材料会在表面产生一种特殊的波纹形貌,波纹的波长和振幅由内至外逐渐减小。利用扫描电镜(SEM)和原子力显微镜(AFM)观测了一种Ti基金属玻璃Ti_(40)Zr_(25)Cu_(12)Ni_3Be_(20)(%,质量分数)被纳秒脉冲激光辐照后表面的波纹形貌。与Zr基和La金属玻璃的实验结果相比,Ti基金属玻璃表面波纹形貌具有更广的范围和更小的特征尺度。在实验观测基础上进行合理的假设来简化模型,假设波纹形貌是由于小振幅表面波在深水域不可压粘性液体中传播,并在传播过程中被凝固而形成的。考虑波群理论和等离子体与熔融液体相互作用的影响,对实验结果进行理论分析。理论分析表明波长短的波传播更快,凝固前波传播的距离更远,所以越靠近边缘波的波长越短,分析结果也可以解释Ti基金属玻璃表面波纹范围更广的原因。此外,激光辐照金属玻璃会电离产生等离子体,通过理论计算发现变化的等离子体速度、密度和粘性等条件也会影响波纹形貌的形成,不同等离子体条件对应不同的波数,亦可通过实验数据观测的波数值反推等离子体条件。
[Abstract]:Pulsed nanosecond laser irradiation of metallic glass materials will produce a special corrugated shape on the surface, and the wavelength and amplitude of the ripples gradually decrease from inside to outside. Scanning Electron Microscopy (SEM) and Atomic Force microscope (AFM) were used to observe the corrugated morphology of a Ti-base metallic glass TiSZ 40ZZ / 25CuD / 12Ni3BeT / 20 / mass fraction (mass fraction) irradiated by nanosecond pulsed laser (nanosecond pulse laser). Compared with the experimental results of Zr-based and La metallic glasses, the corrugated surface morphology of Ti-based metallic glasses has a wider range and smaller characteristic scale. On the basis of experimental observations, reasonable assumptions are made to simplify the model. It is assumed that the ripple morphology is formed by the propagation of small amplitude surface waves in incompressible viscous fluids in deep water and solidification during propagation. Considering the influence of wave group theory and the interaction between plasma and molten liquid, the experimental results are theoretically analyzed. The theoretical analysis shows that the wave propagation of short wavelength is faster and the distance of wave propagation before solidification is longer. Therefore, the closer the wavelength of the edge wave is, the shorter the wavelength is, which can also explain the wider ripple range on Ti based metallic glass surface. In addition, metal glass irradiated by laser will ionize to produce plasma. By theoretical calculation, it is found that the variation of plasma velocity, density and viscosity will also affect the formation of corrugated morphology. Different plasma conditions correspond to different wave numbers. The plasma condition can also be inversely deduced from the wave numerical data.
【作者单位】：北京大学工学院湍流与复杂系统国家重点实验室;中国劳动关系学院安全工程系;
【基金】：国家自然科学基金项目(10732010,10972110,11028206)资助
【分类号】：TG139.8;TG665

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