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Effect of Fe content on microstructure and mechanical properties of Fex(CoCrNi)100-x medium-entropy alloys
Yu Liaoa, Yisi Songa,*, Dezheng Lia, Yiwei Wanga, Zhenhua Yea, Chuanwei Lia,b,*, Jianfeng Gua,b
aInstitute of Materials Modification and Modelling, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
bShanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai, 200240, China
Abstract
The high cost of high- and medium-entropy alloys (H/MEAs) has limited their structural applications, leading to increased interest in cost-effective ferrous MEAs (Fe-MEAs), where microstructure and mechanical properties are strongly influenced by Fe content. In this study, we systematically investigated the microstructural evolution, mechanical properties and deformation mechanisms of Fex(CoCrNi)100-x (x = 25, 40, 50, 62, 64, 66, and71, at.%) MEAs. The results revealed that the constituent phases evolved from a single face-centered cubic (FCC) phase (Fe25, Fe40, and Fe50) to a mixture of FCC and body-centered cubic (BCC) phases (Fe62, Fe64, and Fe66), eventually forming a single BCC phase (Fe71). As the Fe content increased, the yield strength (YS) gradually decreased from ∼394.8 MPa for Fe25 to ∼206.0 MPa for Fe62, while the uniform elongation (UE) remained above 40 % for all alloys. Further increases in Fe content significantly enhanced strength, though at the cost of a substantial reduction in elongation. Fe71 exhibited a high YS of ∼831.0 MPa but with a UE of only ∼1.5 %. In addition to dislocation slip, deformation nanotwins (DTs) were observed in deformed Fe50, and deformation-induced martensitic transformation (DIMT) was detected in deformed Fe64.
Effect of Fe content on microstructure and mechanical properties of Fex(CoCrNi)100-x medium-entropy alloys.pdf
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