Journal Article

A superfine eutectic microstructure and the mechanical properties of CoCrFeNiMox high-entropy alloys

Zhang, Yue, Zhao, Zuofu, Liu, Liang, Xiang, Jun, Wang, Bing, Qi, Jingang, Shang, Jian, Guo, Yong

2018

Overview

A series of CoCrFeNiMox (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 CoCrFeNiMox 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 CoCrFeNiMox 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 Cr9Mo21Ni20 intermetallic compounds. The hardness of the CoCrFeNiMox 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.

• Publisher: Cambridge University Press,Springer International Publishing,Springer Nature B.V
• Subject: Alloy development / Alloy systems / Alloys / Applied and Technical Physics / Biomaterials / Compressive properties / Compressive strength / Crystal structure / Dendritic structure / Ductility / Entropy / Eutectic alloys / Eutectics / Fracture strength / High entropy alloys / Hypereutectic structures / Inorganic Chemistry / Intermetallic compounds / Materials Engineering / Materials research / Materials Science / Mechanical properties / Microstructure / Molybdenum / Nanotechnology / Scanning electron microscopy / Solid solutions / Solidification / Strain / Ultrafines