Ebrahimian Marzieh, Rizi Mohsen Saboktakin, Hong Sun Ig, Kim Jeoung Han
Department of Materials Science and Engineering, Hanbat National University, Daejeon, Republic of Korea.
Department of Materials Science and Engineering, Chungnam National University, Daejeon, Republic of Korea.
Sci Technol Adv Mater. 2023 Mar 14;24(1):2186119. doi: 10.1080/14686996.2023.2186119. eCollection 2023.
The remarkable properties of high-entropy alloys (HEAs) have resulted in their increased research interest and prompted the use of various strategies to enhance their mechanical properties. In this study, the effects of Mo on the hot compressive deformation behavior of carbon-containing FeMnCoCr HEAs in the temperature range of 800-1000°C and strain rate of 0.001-0.1 s was investigated. The microstructural evolutilon and phase structure were characterized by X-ray diffraction and electron backscattered diffraction. The effects of strain, strain rate, and deformation temperature on the thermally activated deformation restoration process of the FeMnCoCrC and FeMnCoCrCMo HEAs during hot compression were represented by the Zener-Hollomon parameter. Dynamic recrystallization was initiated at 800°C with the strain rate of 0.001-0.1 s. The precipitation of the MC carbide along the grain boundaries and within the matrix exerted a strong pinning effect on the grain/subgrain boundaries and promoted dynamic recrystallization through the particle-stimulated nucleation of recrystallization. Moreover, the addition of Mo to the FeMnCoCrC HEA changed the dynamic recrystallization mechanism by reducing the stacking fault energy and enhancing the reverse phase transformation. The heterogeneous microstructure composed of ultrafine, fine, and larger grains in the FeMnCoCrCMo HEA could be obtained by the nucleation of new recrystallized grains at large deformed grain boundaries adjacent to the first necklace structures and shear bands.
高熵合金（HEAs）的卓越性能引发了人们对其研究兴趣的增加，并促使采用各种策略来提高其机械性能。在本研究中，研究了Mo对含碳FeMnCoCr高熵合金在800-1000°C温度范围和0.001-0.1 s应变率下热压缩变形行为的影响。通过X射线衍射和电子背散射衍射对微观结构演变和相结构进行了表征。用Zener-Hollomon参数表示了应变、应变率和变形温度对FeMnCoCrC和FeMnCoCrCMo高熵合金在热压缩过程中热激活变形恢复过程的影响。在800°C、应变率为0.001-0.1 s时开始动态再结晶。MC碳化物沿晶界和基体内部的析出对晶粒/亚晶界产生了强烈的钉扎作用，并通过再结晶的粒子激发形核促进了动态再结晶。此外，向FeMnCoCrC高熵合金中添加Mo通过降低堆垛层错能和增强逆相变改变了动态再结晶机制。通过在与第一个项链状组织和剪切带相邻的大变形晶粒边界处形核新的再结晶晶粒，可以获得FeMnCoCrCMo高熵合金中由超细、细和较大晶粒组成的非均匀微观结构。
