From high entropy alloys to diluted multi-component alloys: Range of existence of a solid-solution. (5th August 2016)

• Record Type: Journal Article
• Authors: Laurent-Brocq, Mathilde; Perrière, Loïc; Pirès, Rémy; Champion, Yannick
• Is Part Of: Materials & design. Volume 103(2016)
• Page Start: 84
• Page End: 89
• Publication Date: 2016-08-05
• Subjects: Multi-component alloys -- High entropy alloys -- Solid solution -- Microstructure -- Thermodynamic modelling; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.04.046
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: In order to systematically compare high entropy alloys (HEA) and conventional diluted multi-component alloys and to observe the transition between both, 13 Crx Mnx Fex Cox Ni100 − 4x multi-component alloys, where x takes values between 2 and 25, were processed so as to reach the stable state and then characterized. A unique fcc solid-solution is formed for a wide range composition, spanning from 0 to 90 at.% of Cr, Mn, Fe and Co. When the sum of Cr, Fe, Mn and Co contents is larger than 90 at.%, the system demixes into two quaternary phases. The existing thermodynamics models are unable to predict the range of existence of the solid-solution for the studied alloys. No microstructural transition between HEA and conventional diluted alloys is observed. The maximization of configurational entropy appears to be neither a sufficient nor a necessary condition to form a HEA. Consequently a new definition for HEA is needed. Graphical abstract: Highlights: The range of existence of a solid-solution for the Crx Mnx Fex Cox Ni100-4x is large. No difference nor transition in the microstructure between HEA and diluted multi-component solid-solutions were observed. Maximizing the configurational entropy is neither sufficient nor necessary to form a multi-component solid-solution. A new definition of high entropy alloys is needed.