论文标题
分析微观结构陷阱对氢辅助疲劳的影响
Analysis of the influence of microstructural traps on hydrogen assisted fatigue
论文作者
论文摘要
我们研究了微观结构陷阱对循环载荷存在下的氢扩散和覆盖的影响。开发了一种用于氢运输的机械，多陷阱模型，将其实现为有限的元素框架，并用于捕获裂纹尖端晶格和捕获的氢浓度的变化，这是负载频率，陷阱结合能和陷阱密度的函数。我们表明，在循环分析过程中，晶格氢浓度获得的最大值表现出对加载频率与有效扩散系数之间比率的显着敏感性。这对于氢预荷样品（封闭系统）和暴露于氢（开放系统）的永久源的样品都可以观察到这一点。实验用于通过绘制输出与惰性环境中的测试相同的频率范围来确定临界互惠率。然后，我们定量研究并讨论在循环载荷存在下，开发具有较高陷阱密度的材料在减轻封闭中的含义。结果表明，与静态情况不同，增加“有益陷阱”的密度是设计抗氢辅助疲劳的合金和开放系统的可行策略。
We investigate the influence of microstructural traps on hydrogen diffusion and embrittlement in the presence of cyclic loads. A mechanistic, multi-trap model for hydrogen transport is developed, implemented into a finite element framework, and used to capture the variation of crack tip lattice and trapped hydrogen concentrations as a function of the loading frequency, the trap binding energies and the trap densities. We show that the maximum value attained by the lattice hydrogen concentration during the cyclic analysis exhibits a notable sensitivity to the ratio between the loading frequency and the effective diffusion coefficient. This is observed for both hydrogen pre-charged samples (closed-systems) and samples exposed to a permanent source of hydrogen (open-systems). Experiments are used to determine the critical concentration for embrittlement, by mapping the range of frequencies where the output is the same as testing in inert environments. We then quantitatively investigate and discuss the implications of developing materials with higher trap densities in mitigating embrittlement in the presence of cyclic loads. It is shown that, unlike the static case, increasing the density of "beneficial traps" is a viable strategy in designing alloys resistant to hydrogen assisted fatigue for both closed- and open-systems.
