Fine-Grained FeCoNi(CuAl)x High Entropy Alloys: Phase Transformation, Microstructure Evolution and Mechanical Properties
| Autor: | Yan Long, Li Guiqi, Haiyan Peng, Xiaobiao Liang |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
phase transformation
Materials science Materials Science (miscellaneous) Alloy Spark plasma sintering Sintering 02 engineering and technology mechanical properties engineering.material 010402 general chemistry lcsh:Technology 01 natural sciences Phase (matter) Composite material high-entropy alloys lcsh:T High entropy alloys 021001 nanoscience & nanotechnology Microstructure fine-grained Grain size 0104 chemical sciences Grain growth engineering 0210 nano-technology spark plasma sintering |
| Zdroj: | Frontiers in Materials, Vol 7 (2020) |
| ISSN: | 2296-8016 |
| DOI: | 10.3389/fmats.2020.537812 |
| Popis: | A series of fine-grained FeCoNi(CuAl)x (x = 0, 0.4, 0.6, 0.8, 1.0) medium-entropy alloy (MEA) and high-entropy alloys (HEAs) were fabricated by Mechanical Alloying (MA) and Spark Plasma Sintering (SPS). The effect of Al and Cu content (x) on phase composition, microstructure, and mechanical properties of the alloys was investigated. Experimental results show that the crystal structure of FeCoNi(CuAl)x alloy transforms from single (face-centered cubic) FCC phase for x = 0 to FCC + BCC duplex phases for x = 0.4∼1.0, with the fraction of (body-centered cubic) BCC phase gradually increasing with the increase of x. Adding a low content of Al and Cu elements to FeCoNi alloy can significantly hinder the grain growth during sintering process, the average grain size of FCC phase decreases from 0.95 to 0.30 µm at x = 0.4. However, the grain sizes of FCC and BCC phases gradually grow up when x increases from 0.4 to 1.0. The variation in grain size indicates that the atomic diffusion rate of sintered alloy may be influenced by the sluggish diffusion effect in HEA as well as the content of Al and Cu with lower melting points. Mechanical properties of the HEAs are mainly affected by the volume fraction of BCC phase. The compressive yield strength and hardness of HEAs are improved at first and then slightly reduced, while the plasticity drops down continuously with the increase of x. The bulky HEA achieved excellent comprehensive mechanical properties with a compressive yield strength of 1,467.7 MPa and plastic strain to failure of 24.9% at x = 0.6, due to the fine duplex microstructure. |
| Databáze: | OpenAIRE |
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