Quantitative Approach for Determining the Critical Volume Fraction for the Transition from Internal to External Oxidation
Quantitative Approach for Determining the Critical Volume Fraction for the Transition from Internal to External Oxidation
复制标题
确定从内部氧化到外部氧化转变的临界体积分数的定量方法
作者：
Wei Zhao;Yihong Kang;J. M. A. Orozco;B. Gleeson
提出了一种计算内氧化向外氧化转变的临界体积分数Fv*的理论方法。重点研究了氧化初期内氧化物体积分数的演化。通过考虑氧在合金中的有效扩散系数(Doef)，考虑了形成内部氧化物析出物的演化阻塞效应，建立了计算Fv*的公式。基于这一物理过程，可以产生三种类型的氧化行为，具体取决于合金的性质和暴露的气氛。进一步讨论了预测值和实验确定的Fv*值之间的剩余差异，以完善该参数的理论预测。
A theoretical approach is presented to calculate the critical volume fraction fv* for the transition from internal to external oxidation. The focus was on the evolution of internal-oxide volume fraction during the initial stage of oxidation. An equation to calculate fv* was developed by considering an effective diffusion coefficient of oxygen in the alloy (DOeff) which takes into account the evolving blocking effect by forming internal oxide precipitates. Based on this physical process, three types of oxidation behavior can result, depending on the properties of the alloy and exposure atmosphere. Further discussions on the remaining discrepancy between predicted and experimentally-determined fv* values are provided for refinement on the theoretical prediction of this parameter.