A superfine eutectic microstructure and the mechanical properties of CoCrFeNiMox high-entropy alloys. Issue 19 (14th October 2018)

• Record Type: Journal Article
• Authors: Guo, Yong; Liu, Liang; Zhang, Yue; Qi, Jingang; Wang, Bing; Zhao, Zuofu; Shang, Jian; Xiang, Jun
• Is Part Of: Journal of materials research. Volume 33:Issue 19(2018)
• Page Start: 3258
• Page End: 3265
• Publication Date: 2018-10-14
• Subjects: high-entropy alloy, -- crystal structure, -- eutectic microstructure, -- mechanical properties, -- Mo content; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1557/jmr.2018.177
• Languages: English
• ISSNs: 0884-2914

Abstract

Abstract: Abstract : A series of CoCrFeNiMo x ( x = 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2) high-entropy alloys were designed to develop a eutectic high-entropy alloy system and to acquire a superfine eutectic structure. The results show that for the CoCrFeNiMo x alloys, with the increase of Mo content from 0.2 to 1.2, the microstructures shift from a typical dendrite structure to a hypoeutectic microstructure ( x = 0.6), and then to a fully eutectic microstructure ( x = 0.8) with a lamellar spacing only 110 nm, and finally culminate in the hypereutectic structure ( x = 1.0, x = 1.2). The XRD results show that CoCrFeNiMo x alloys have a single FCC phase when x is 0.2 or 0.4. When Mo content is over 0.6, it begins to separate Cr9 Mo21 Ni20 intermetallic compounds. The hardness of the CoCrFeNiMo x alloys is increasing significantly from 172.8 to 763.7 HV with the increase of Mo content. Meanwhile, the fracture strength increased but the ductility decreases. Among these alloys, the CoCrFeNiMo0.6 alloy shows excellent integrated mechanical properties of compressive fracture strength and strain, which are 2051 Mpa and 23%, respectively.