Hydrogen-Assisted Brittle Fracture Behavior of Low Alloy 30CrMo Steel Based on the Combination of Experimental and Numerical Analyses.
Hydrogen-Assisted Brittle Fracture Behavior of Low Alloy 30CrMo Steel Based on the Combination of Experimental and Numerical Analyses.
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基于实验与数值分析相结合的低合金30CrMo钢氢辅助脆性断裂行为
DOI：
10.3390/ma14133711
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发表时间：
2021-07-02
期刊：
影响因子：
--
通讯作者：
Zeng B
中科院分区：
文献类型：
--
作者：
Li Y;Zhang K;Lu D;Zeng B
对低合金30 CrMo钢的压缩拉伸（CT）试样充氢后进行断裂韧性试验。实验结果表明，随着氢脆指数的增加，裂纹扩展速率增加，裂纹扩展阻力（CTOD-R曲线）降低。此外，过渡的微观结构断裂机制从韧性（微孔聚结（MVC））没有氢混合准解理（QC）断裂和QC +晶间（IG）断裂与氢观察。氢增强脱粘（HEDE）机制的特点是占主导地位的HE机制。根据试验结果，采用应力场与氢扩散场耦合的方法，结合内聚区应力分析，利用ABAQUS软件对氢致脆性断裂行为进行了数值模拟。采用梯形牵引-分离定律（TSL），对无氢条件下的载荷-位移和J积分实验曲线进行最佳拟合，得到临界分离距离为0.0393 mm，内聚强度为2100 MPa的TSL初始参数。HEDE是通过氢在TSL的影响，并估计初始氢浓度的基础上匹配的数值和实验的负载线位移曲线与氢。模拟结果表明，计算得到的CTOD-R曲线随初始氢浓度的变化趋势与实验结果基本一致，但计算得到的CTOD值略高。数值和实验结果的比较分析表明，耦合模型可以提供设计和预测，计算氢辅助断裂行为之前，广泛的实验室测试，提供的材料特性和适当校准的TSL参数是已知的。
Compact-tension (CT) specimens made of low alloy 30CrMo steels were hydrogen-charged, and then subjected to the fracture toughness test. The experimental results revealed that the higher crack propagation and the lower crack growth resistance (CTOD-R curve) are significantly noticeable with increasing hydrogen embrittlement (HE) indexes. Moreover, the transition in the microstructural fracture mechanism from ductile (microvoid coalescence (MVC)) without hydrogen to a mixed quasi-cleavage (QC) fracture and QC + intergranular (IG) fracture with hydrogen was observed. The hydrogen-enhanced decohesion (HEDE) mechanism was characterized as the dominant HE mechanism. According to the experimental testing, the coupled problem of stress field and hydrogen diffusion field with cohesive zone stress analysis was employed to simulate hydrogen-assisted brittle fracture behavior by using ABAQUS software. The trapezoidal traction-separation law (TSL) was adopted, and the initial TSL parameters from the best fit to the load-displacement and J-integral experimental curves without hydrogen were calibrated for the critical separation of 0.0393 mm and the cohesive strength of 2100 MPa. The HEDE was implemented through hydrogen influence in the TSL, and to estimate the initial hydrogen concentration based on matching numerical and experimental load-line displacement curves with hydrogen. The simulation results show that the general trend of the computational CTOD-R curves corresponding to initial hydrogen concentration is almost the same as that obtained from the experimental data but in full agreement, the computational CTOD values being slightly higher. Comparative analysis of numerical and experimental results shows that the coupled model can provide design and prediction to calculate hydrogen-assisted fracture behavior prior to extensive laboratory testing, provided that the material properties and properly calibrated TSL parameters are known.
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发表时间：
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期刊：
Materials (Basel, Switzerland)
影响因子：
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