Isothermal oxidation behaviors of FeCoV and FeCoVNb alloys
Isothermal oxidation behaviors of FeCoV and FeCoVNb alloys
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FeCoV和FeCoVNb合金的等温氧化行为
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Coate
中科院分区：
文献类型：
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作者：
Z. Turgut;J. Horwath;M. Huang;J. Coate
本文研究了两种铁钴基合金在500 °C下恒温氧化5000 h的情况。这两种合金都表现出无裂纹的氧化层，由无孔隙的富铁外层和富含溶质的内层组成，内层由溶质氧化物和孔隙组成。X射线衍射测量揭示了MO-Fe 2 O 3型（其中M=Co、Nb和/或V）尖晶石结构沿着Fe 2 O 3的存在。分析表明，两种合金的氧化均遵循抛物线规律，含铌合金的氧化速率较高。氧化试样的屈服强度（σ0）与在惰性气氛下类似老化的试样的屈服强度（σ0）的比较表明，存在两种竞争机制。表面氧化降低了屈服强度，而铁钴基体内部的沉淀反应增加了基体的屈服强度。
The present study investigates the isothermal oxidation of two iron-cobalt based alloys at 500 °C for up to 5000 h. Both alloys exhibit crack-free oxide layers consist of a porosity-free iron rich outer layer and a solute rich inner layer populated with islands of solute oxides and porosities. X-ray diffraction measurements reveal the presence of MO–Fe2O3-type (where M=Co, Nb, and/or V) spinel structures along with Fe2O3. Analysis shows that the oxidation follows the parabolic rate law for both alloys with niobium containing alloy exhibiting a higher oxidation rate. Comparison of yield strengths (σ0) of oxidized specimens to those aged similarly under an inert atmosphere indicates that two competing mechanisms occur. Surface oxidation decreases the yield strength while precipitation reactions inside the iron-cobalt matrix increase the yield strength of the matrix.