材料氢脆涡流评价的有限元仿真研究*

针对扩散氢在材料内部渗透和聚集引起的氢脆问题，提出了一种基于涡流信号的表征方法。以电化学充氢试样为研究对象，首先基于Fick定律计算了电化学充氢过程中试样的氢分布，然后基于电磁感应原理运用COMSOL Multiphysics建立了不同氢分布状态下材料氢脆的涡流检测有限元模型，通过数值计算分析时谐电磁场激励下试样的感生涡流场分布及检测线圈的电磁场量图，并通过原位拉伸实验定量表征氢脆程度，最后分析了氢脆指数-涡流响应信号之间的关联机制，进行实验验证。研究结果表明，金属材料的氢脆程度与所含氢含量密切相关，时谐电磁场作用下的涡流信号与氢脆程度呈现线性相关，验证了材料氢脆涡流评价的有限元模型的有效性。

Finite element simulation study on eddy current evaluation of material hydrogen embrittlement

Aiming at the problem of hydrogen embrittlement caused by diffusion and accumulation of hydrogen in materials, a characterization method based on eddy current signal is proposed. Taking the electrochemical hydrogen charging sample as the research object, firstly, the hydrogen distribution of the sample in the electrochemical hydrogen charging process is calculated based on Fick''s law. Then, based on the principle of electromagnetic induction, the eddy current detection finite element model of material hydrogen embrittlement under different hydrogen distributions is established by using COMSOL multiphysics. The distribution of induced eddy current field of the sample excited by time-harmonic electromagnetic field and the electromagnetic field diagram of the detection coil are analyzed by numerical calculation. The in-situ tensile test quantitatively characterized the degree of hydrogen embrittlement. The correlation mechanism between hydrogen embrittlement index and eddy current response signal was analyzed for experimental verification. The results show that the degree of hydrogen embrittlement of metal materials is closely related to the hydrogen content, and the eddy current signal under the action of a time-harmonic electromagnetic field is linearly related to the degree of hydrogen embrittlement, which verifies the effectiveness of the finite element model for eddy current evaluation of material hydrogen embrittlement.