Thermal oxidation characteristics of Fex(CoCrMnNi)100-x medium and high-entropy alloys
Thermal oxidation characteristics of Fex(CoCrMnNi)100-x medium and high-entropy alloys
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DOI：
10.1016/j.intermet.2020.106757
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发表时间：
2020-05-01
期刊：
影响因子：
4.4
通讯作者：
Lee, Unhae
中科院分区：
文献类型：
--
作者：
Agustianingrum, Maya Putri;Latief, Fahamsyah Hamdan;Lee, Unhae
研究了Fe-x(CoCrMnNi)(100-x)高熵合金(x=20和40at.%)和中熵合金(x=60at.%)在空气气氛下900℃到1100℃范围内的热氧化行为。合金的氧化动力学遵循抛物线定律，氧化速率常数随着铁含量和温度的增加而增加。 Fe含量的添加降低了合金的构型熵和活化能，支持金属原子扩散的加速。此外，表面形成的氧化皮很大程度上取决于合金成分。一般来说，所有合金在900℃氧化后均形成Cr2O3内层、尖晶石（NiCr2O4和CoMn2O4）中间层以及Fe3O4和Mn3O4外层。另一方面，含 60 at.% Fe 的合金在 1100 ℃ 氧化后观察到严重的内部氧化和气孔。此外，由于柯肯达尔效应而形成气孔，作为扩散路径和反应场所，有利于氧化过程。
The thermal oxidation behavior of Fe-x(CoCrMnNi)(100-x) high-entropy alloys (x = 20 and 40 at.%) and medium-entropy alloy (x = 60 at.%) at temperatures ranging from 900 degrees C to 1100 degrees C under air atmosphere was investigated. The oxidation kinetics of the alloys followed the parabolic law, indicated by the increase of oxidation rate constants with increasing Fe content and temperature. The addition of Fe content lowered the configurational entropy and activation energy of the alloys, supporting the acceleration of metal atoms diffusion. Furthermore, the oxide scales formed on the surface were strongly dependent on the alloy composition. In general, a Cr2O3 inner layer, spinels (NiCr2O4 and CoMn2O4) as intermediate layers, and the outer layers of Fe3O4 and Mn3O4 were formed after oxidation at 900 degrees C in all alloys. On the other hand, severe internal oxidation and pores were observed in the alloy containing 60 at.% of Fe after oxidation at 1100 degrees C. In addition, the pores were formed due to the Kirkendall effect, acting as diffusion path and reaction place which may facilitate the oxidation process.