Samoilova Olga, Pratskova Svetlana, Shaburova Nataliya, Ostovari Moghaddam Ahmad, Trofimov Evgeny
Department of Materials Science, Physical and Chemical Properties of Materials, South Ural State University, 76 Lenin Av., 454080 Chelyabinsk, Russia.
Research and Innovation Services, South Ural State University, 76 Lenin Av., 454080 Chelyabinsk, Russia.
Materials (Basel). 2025 Aug 6;18(15):3701. doi: 10.3390/ma18153701.
The microstructure, phase composition, and high-temperature oxidation resistance of Fe-free AlCoCrNiNb and AlCoCrNiNb high-entropy alloys (HEAs) were investigated. In the as-cast HEAs, niobium was found to mainly release as a Laves phase in the interdendritic region, and its solubility in the dendrites of the BCC solid solution was about 2 at.%. Both samples exhibited parabolic behavior during 100 h oxidation at 1000 °C and 1100 °C. The AlCoCrNiNb alloy demonstrated higher resistance to high-temperature oxidation compared to AlCoCrNiNb. The specific weight changes after 100 h of isothermal holding at 1000 °C and 1100 °C were 0.65 mg/cm and 1.31 mg/cm, respectively, which are superior compared to the Fe-containing HEAs. Cr was revealed to play an important role in the oxidation behavior of the HEAs, decreasing the parabolic oxidation rate constant and increasing the activation energy of the oxidation process in the alloys.
研究了无铁AlCoCrNiNb和AlCoCrNiNb高熵合金（HEAs）的微观结构、相组成和高温抗氧化性能。在铸态高熵合金中，发现铌主要以拉夫斯相的形式在枝晶间区域析出，其在体心立方固溶体枝晶中的溶解度约为2原子%。在1000℃和1100℃下氧化100小时期间，两个样品均表现出抛物线行为。与AlCoCrNiNb相比，AlCoCrNiNb合金表现出更高的高温抗氧化性。在1000℃和1100℃等温保持100小时后的比重量变化分别为0.65毫克/平方厘米和1.31毫克/平方厘米，与含铁高熵合金相比更优。研究发现，Cr在高熵合金的氧化行为中起重要作用，降低了抛物线氧化速率常数，并增加了合金中氧化过程的活化能。
