Microstructure evolution of a multi-track AlCoCrFeNi high entropy alloy coating fabricated by laser cladding
Microstructure evolution of a multi-track AlCoCrFeNi high entropy alloy coating fabricated by laser cladding
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DOI：
10.1016/j.matchar.2021.111660
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发表时间：
2021-12-09
影响因子：
4.7
通讯作者：
Zairi, Fahmi
中科院分区：
文献类型：
--
作者：
Guo, Weimin;Ding, Ning;Zairi, Fahmi
为了了解AlCoCrFeNi高熵合金（HEA）涂层在高环境温度下的组织演变特征，将激光熔覆的AlCoCrFeNi高熵合金（HEA）涂层分别加热至700 ℃、900 ℃和1100 ℃，保温30 min，然后在空气中冷却。研究了涂层界面和涂层区的显微组织和显微硬度。在界面区，未处理试样界面与涂层交界处存在面心立方块状物，涂层中存在体心立方单相。在700 ℃处理的涂层中，主要的FCC块体保留，而在900 ℃和1100 ℃处理的涂层中，它们消失。然而，新的FCC颗粒形成，而不是在界面附近。在涂层方面，未处理和700 ℃处理的涂层均获得BCC单相。在900 ℃和1100 ℃热处理的涂层中，大量的FCC和σ（富铬碳化物）颗粒主要分布在BCC相基体的晶界上，BCC相发生调幅分解。700 ℃热处理涂层的显微硬度由于时效硬化效应而略高于未处理涂层，而900 ℃和1100 ℃热处理涂层的显微硬度由于软FCC相的形成而远低于未处理和700 ℃热处理涂层。1100 ℃热处理涂层的显微硬度略低于900 ℃热处理涂层的显微硬度，这是由于σ粒子的粗化和旋节分解结构所致。
In order to understand the microstructure evolution characteristics of AlCoCrFeNi high entropy alloy (HEA) coating at high environmental temperatures, a laser cladded AlCoCrFeNi HEA coating is heated to 700 degrees C, 900 degrees C and 1100 degrees C respectively, holding for 30 min and cooled in air. Microstructure and micro-hardness of the treated coatings are investigated, in both interface and coating areas. In interface area, FCC blocks exist on the boundary of interface and coating in untreated specimen, besides the BCC single phase in coating. The primary FCC blocks remain in 700 degrees C treated coating, while they disappear in 900 degrees C and 1100 degrees C treated coatings. However, new FCC particles are formed instead near interface. In coating area, BCC single phase is acquired in untreated and 700 degrees C treated coatings. In 900 degrees C and 1100 degrees C treated coatings, lots of FCC and sigma (Cr-rich carbide) particles are distributed mainly on grain boundaries of BCC phase matrix and spinodal decomposition occurs to BCC phase. Micro-hardness of 700 degrees C treated coating is slightly higher than that of untreated coating due to the age hardening effect, while the micro-hardness of 900 degrees C and 1100 degrees C treated coatings are much lower than that in untreated and 700 degrees C treated coatings due to the formation of soft FCC phase. Micro-hardness of 1100 degrees C treated coating is slightly lower than that of 900 degrees C treated coating due to the coarsening of sigma particles and spinodal decomposed structures.