https://scholars.lib.ntu.edu.tw/handle/123456789/598360
標題: | Effects of cerium addition on microstructures and mechanical properties of CoCrNi medium entropy alloy films | 作者: | Lin Y.Y.-T Li C.-L Hsueh C.-H. CHUN-HWAY HSUEH |
關鍵字: | Ce addition;Mechanical properties;Medium entropy alloy films;Microstructure;Rare-earth element;Compression testing;Elastic moduli;Entropy;Hardness;Iron;Lanthanum;Magnetron sputtering;Metallic films;Nanocrystals;Nickel;Rare earths;Alloy film;Ce contents;Mechanical;Medium entropy;Medium entropy alloy film;Microstructures and mechanical properties;Property;Radio-frequency magnetron co-sputtering;Rare-earths | 公開日期: | 2021 | 卷: | 424 | 來源出版物: | Surface and Coatings Technology | 摘要: | In this work, the effects of rare-earth element Ce addition on the microstructures and mechanical properties of (CoCrNi)100-xCex (x = 0, 1.05, 2.61, 4.2, 5.96) medium entropy alloy films (MEAFs) were investigated. A series of (CoCrNi)100-xCex MEAFs was fabricated by radio frequency magnetron co-sputtering. The XRD and TEM results showed that the structure transformed from FCC to FCC + HCP at x = 2.61. Also, as Ni precipitated with Ce to form CeNi5 HCP phase, the localized depletion of Ni would encourage CoCrNi to transform from FCC to HCP phase. With the further increase in Ce content, Ce4.2 film became mixed nanocrystalline and amorphous structures and Ce5.96 film was fully amorphous. The nanoindentation and micro-pillar compression tests were conducted to study the mechanical properties of films. Both the hardness and Young's modulus showed an initial increase, reached the maxima of ~10 GPa and ~200 GPa, respectively, at x = 1.05, and then decreased with the increasing Ce content. The trends of yield strength and ultimate strength versus Ce content were similar to hardness. These results demonstrated that small amounts of Ce addition could strengthen CoCrNi MEAFs due to solid solution strengthening. However, excessive Ce addition would reduce the grain size to below ~10 nm and weaken the CoCrNiCe system due to the inverse Hall-Petch effect. ? 2021 Elsevier B.V. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113944648&doi=10.1016%2fj.surfcoat.2021.127645&partnerID=40&md5=468e668bc4e7f33ade539afa1a464f13 https://scholars.lib.ntu.edu.tw/handle/123456789/598360 |
ISSN: | 02578972 | DOI: | 10.1016/j.surfcoat.2021.127645 |
顯示於: | 材料科學與工程學系 |
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