激光诱导击穿光谱分析中钛合金样品制备方法研究

发布时间：2018-06-13 04:17

本文选题：激光诱导击穿光谱(LIBS) + 钛合金　；参考：《冶金分析》2017年03期

【摘要】：Ti-47.5Al-2.5V-1.0Cr钛合金具有高温延展性好、高温强度大的特点,有用于铸造涡轮、涡流器、叶片等高温部件的潜力。在用激光诱导击穿光谱(LIBS)对合金或部件内部定量分析前,需预先将被分析钛合金样品和钛合金标准样品用相同的方法制备以去除表面氧化层、铸造反应层和污染物。鉴于该钛合金为室温脆性材料,不适于切削制备样品,宜采用磨抛方法制备样品,而磨抛制备样品时因发热粘滞会造成样品表面污染,影响LIBS分析钛合金中成分。实验用LIBS评价光谱磨样机磨制、金相磨样机磨制、手工磨制、手工抛光、辉光氩离子轰击等几种方法去除不同组织钛合金标样表面氧化层、污染物的效果。通过LIBS分析发现,样品制备过程中污染来源于制造砂纸的胶接剂,磨制线速度、磨料粒度、抛光方向影响制备效果,且样品的组织也影响污染物去除效果。用碳化硅砂纸光谱磨样机高速磨制钛合金表面碳污染层深度大,达15μm,高于水冷金相磨样机中速磨制的碳污染层深度,说明温度高促进碳在钛合金中的扩散;中低速磨制时,使用的砂纸标号越高,含碳、钙的污染物在样品表面附着增加。中速磨制时,与α相亲和力强的钙、铝等元素在α组织的钛合金扩散深度较α+β、α_2+γ组织钛合金大,钙污染深度达10μm,而碳在不同组织的钛合金表面扩散没有明显差别。手工低速磨制时,在钛合金表面上的碳、钙污染层较浅,深度为1~3μm,与磨痕深度一致。双向或沿磨削纹理抛光效果优于垂直纹理抛光效果,残留污染物深度不超过1μm,与辉光氩离子轰击效果相近。实验研究解决了钛合金样品制备易受污染的问题,LIBS分析碳等元素的校准曲线得到改善,测量精度得到提高。对于Ti-47.5Al-2.5V-1.0Cr钛合金样品分析的结果同其他方法的对照结果一致性较好。
[Abstract]:Ti-47.5Al-2.5V-1.0Cr titanium alloy has the characteristics of good ductility at high temperature and high strength at high temperature. It has the potential to be used in casting turbine, eddy current, blade and other high temperature components. Before laser induced breakdown spectroscopy (LIBS) is used to quantitatively analyze the alloys or components, the samples of the analyzed titanium alloys and the standard samples of the titanium alloys should be prepared in the same way in order to remove the surface oxidation layer, casting reaction layer and contaminants. Because the titanium alloy is a brittle material at room temperature, it is not suitable for cutting to prepare the sample. The grinding and polishing method should be used to prepare the sample. However, the surface contamination of the sample will be caused by the heat viscosity during the grinding and polishing, which will affect the analysis of the composition of the titanium alloy by LIBS. LIBS was used to evaluate the effect of removing oxidation layer and contaminant on the surface of titanium alloy standard samples with different tissues by means of Libs grinding, metallographic grinding, manual polishing and glow argon ion bombardment. It was found by LIBS analysis that the contamination in the process of sample preparation was caused by the binder of sand paper, the linear speed of grinding, the particle size of abrasive, the direction of polishing, and the structure of the sample also affected the removal effect of pollutants. The depth of carbon pollution layer on titanium alloy surface by high speed grinding with silicon carbide sandpaper is 15 渭 m, which is higher than that produced by rapid grinding in water-cooled metallographic grinding prototype, indicating that high temperature can promote the diffusion of carbon in titanium alloy. The higher the label of sand paper used, the more carbon and calcium contaminants are attached to the surface of the sample. In the medium speed grinding, the diffusion depth of 伪 -phase titanium alloy with strong affinity to 伪 phase, such as calcium and aluminum, is larger than that of 伪尾, 伪 -2 纬 structure titanium alloy, and the depth of calcium contamination is 10 渭 m, while the diffusion of carbon on the surface of different microstructure titanium alloy has no obvious difference. The carbon and calcium contamination layer on the surface of titanium alloy is shallow, and the depth is 1 ~ 3 渭 m, which is consistent with the wear depth. The polishing effect of bidirectional or edge-grinding texture is better than that of vertical texture polishing, and the depth of residual pollutants is less than 1 渭 m, which is similar to that of glow argon ion bombardment. The problem of easy contamination in the preparation of titanium alloy samples has been solved experimentally. The calibration curve of carbon and other elements in Libs analysis has been improved, and the measurement accuracy has been improved. For Ti-47.5Al-2.5V-1.0Cr titanium alloy samples, the results are in good agreement with those obtained by other methods.
【作者单位】：钢铁研究总院;
【基金】：国家重大科学仪器设备开发专项(2012YQ20018208)
【分类号】：TG146.23;TG115.33

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