316L奥氏体不锈钢低温表面渗碳的数值分析

发布时间：2018-05-02 23:06

本文选题：奥氏体不锈钢 + 表面强化　；参考：《金属学报》2015年12期

【摘要】：针对316L奥氏体不锈钢表面强化,进行了低温表面渗碳实验并测量了渗后试样渗碳层内C浓度沿深度方向的分布.建立了以"陷阱-去陷阱"质量传递机制为基础的动力学模型,认为Cr原子在C的扩散过程中对C原子具有陷阱作用,利用该模型计算出渗后试样中C浓度沿渗层深度方向的分布,并与实验结果进行比较.结果表明,实验测得的C浓度沿渗层深度方向的分布形状呈现凸状,与简单Fick定律得出来的结果不同,而基于"陷阱-去陷阱"模型得到的计算结果与实验结果符合较好,表明陷阱作用在C扩散过程中起重要作用.Cr原子通过对C原子陷阱作用,降低C的扩散系数,对实验数据拟合得到C的去陷阱激活能为165 k J/mol.所提出模型仅适用于未发生碳化物析出的低温渗碳,且并未考虑扩散应力的影响.
[Abstract]:Aiming at the surface strengthening of 316L austenitic stainless steel, the low temperature surface carburization experiment was carried out and the distribution of C concentration along the depth in the Carburizing layer was measured. A kinetic model based on the mass transfer mechanism of "trapping and detrapping" is established. It is considered that Cr atoms have trap effect on C atoms during the diffusion of C atoms. The distribution of C concentration along the depth of permeation layer was calculated by this model, and the results were compared with the experimental results. The results show that the distribution shape of C concentration along the depth of permeation layer is convex, which is different from that obtained by simple Fick's law, but the calculated results based on the "trapping-detrap" model are in good agreement with the experimental results. It is shown that the trap action plays an important role in the process of C diffusion. The diffusion coefficient of C is reduced by the trap action of Cr atom. The activation energy of detrap activation of C is 165k / mol by fitting the experimental data. The proposed model is only suitable for low temperature Carburizing without carbide precipitation, and the effect of diffusion stress is not considered.
【作者单位】：南京工业大学机械与动力工程学院;
【基金】：国家自然科学基金项目51475224 江苏省高校自然科学研究项目14KJA470002资助~~
【分类号】：TG156.81

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