微合金钢中纳米碳化物分析方法

Detection method of nano-carbide precipitates in microalloyed steel

针对Ti微合金钢,分别采用直接减薄、萃取复型以及无损电解等方法分析钢中纳米碳化物,并将三者检测结果进行对比.研究结果表明:对于直接减薄样品而言,可获得纳米碳化物与基体的取向关系,并分析纳米碳化物的形成过程;而萃取复型和无损电解样品则可较为轻松的观察到直接减薄样品不易观察的微量MC型纳米碳化物(M3C/MC质量分数高达45).同时,由于直接减薄和萃取复型样品仅能观察某一平面的纳米碳化物,而无损电解可获得某一尺寸立方体内的纳米碳化物,故后者检测结果更具有代表性和可重复性.此外,无损电解提取纳米碳化物后,结合化学相分析、X射线小角散射等方法可获得纳米碳化物的物相组成和粒度分布特征,检测结果更为全面.

The nano-carbide precipitates in Ti microalloyed steel are obtained through direct thinning.Extraction replica and nondestructive electrolysis extraction, and different detection methods of nano-carbide precipitates are also compared.In the case of direct thinning, the orientation relationship between the nano-carbide precipitates and the matrix can be identified and used to analyze the formation process of nano-carbide precipitates.Since the M3C/MCmass fraction is more than 45, the MC-type carbide is more difficult to be observed for the direct thinning as compared in the case of extraction replica and nondestructive electrolysis extraction.In addition, direct thinning and extraction replica are only used to observe nano-carbide precipitates in a plane, while nondestructive electrolysis extraction can be used to observe the nano-carbide precipitates in a cube with a certain size, thus delivering representative and repeatable test results.Furthermore, after obtaining the nano-carbide precipitates by nondestructive electrolysis extraction, the phase composition and the particle size distribution of nano-carbide precipitates can be investigated through chemical phase analysis and X-ray small angle scattering.Therefore, the analysis results of nano-carbide precipitates obtained by nondestructive electrolysis extraction are more comprehensive.