Design of metastable complex-concentrated alloys through composition tailoring. (December 2022)

• Record Type: Journal Article
• Authors: Nam, Seungjin; Kim, Sang Jun; Yoon, Kook Noh; Kim, Moon J.; Quevedo-Lopez, Manuel; Hwang, Jun Yeon; Park, Eun Soo; Choi, Hyunjoo
• Is Part Of: Materials & design. Volume 224(2022)
• Publication Date: 2022-12
• Subjects: Alloy design -- Multilayer thin film -- Solid-state alloying -- Composition-dependent properties -- Metastable complex-concentrated alloy; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.111391
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: We proposed alloy exploration approach to develop CCAs with customized properties. A series of CoCrFeNi-based alloy thin films were produced via solid-state alloying. Contour maps for composition-dependent property provided a guideline for alloy design. The ratio of Co/Ni was the key point to improve mechanical properties of alloys. Newly developed MSCCAs revealed mechanical properties of good work-hardening ability. Abstract: To develop alloys with high strength and reasonable ductility, CoCrFeNi-based metastable complex-concentrated alloys were designed using composition–property contour maps. The map was constructed by exploring the phase stability and mechanical behaviors of a series of CoCrFeNi alloy thin films synthesized via solid-state alloying of multilayer thin films. The concentrations of Co and Ni were key to activate metastable deformation behaviors by reducing the stacking fault energy of alloys and improve solid-solution strengthening, as expected from the atomic-level complexity related to the electronegativity difference. By optimizing the Co and Ni concentrations based on the composition-phase/mechanical property contour maps, we activated the combined deformation behavior of mechanical twinning and phase transformation. This resulted in a Co33 Cr25 Fe25 Ni17 metastable complex-concentrated alloy with excellent tensile properties—yield strength of 234 MPa, ultimate tensile strength of 720 MPa, and elongation to failure of 80%. The proposed approach provides a useful guideline for the design of complex-concentrated alloys with customized properties through property predictive control.