Reactive interdiffusion of an Al film and a CoCrFeNi high-entropy alloy. (April 2022)

• Record Type: Journal Article
• Authors: Zhang, Z.Q.; Ketov, S.V.; Fellner, S.; Sheng, H.P.; Mitterer, C.; Song, K.K.; Gammer, C.; Eckert, J.
• Is Part Of: Materials & design. Volume 216(2022)
• Publication Date: 2022-04
• Subjects: Reactive diffusion -- High-entropy alloy -- Deposition -- Phase evolution; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.110530
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Reactive interdiffusion of a CoCrFeNi high-entropy alloy (HEA) and a sputter deposited Al layer was carried out. The phase formation during isothermal annealing at 773 K was studied using structural characterization at multiple length scales. The diffusion and phase evolution are controlled by the Gibbs free energy gradient in front of the interface. The sluggish diffusion effect in HEAs does not play a dominant role in determining phase constitution in the current system. Surface modification in HEAs can be realized through a combination of sputter deposition with annealing. Abstract: Diffusion plays a significant role in phase formation and transformation in solid-state alloys. In order to determine the influence of element diffusion on the phase formation and transition behavior in a high-entropy alloy (HEA), a systematic study on the reactive diffusion of Al and a CoCrFeNi HEA was carried out. It is demonstrated that thermodynamic and kinetic effects play a coupled role in the phase evolution in the HEA, among which the thermodynamic effect governs the evolution of major phases. The diffusion direction of the elements is controlled by the Gibbs free energy gradient in front of the interface, while the sluggish diffusion effect does not play a dominant role during reactive diffusion. At an annealing temperature of 773 K, the enthalpy of mixing dominates the total energy and therefore has a significant impact on the phase evolution during reactive diffusion.