Phase equilibria and mechanical properties of a multicomponent medium entropy Cr40Co40Ni20 alloy

• Grant number: 19/00229-4
• Support type: Scholarships in Brazil - Master
• Effective date (Start): April 01, 2019
• Effective date (End): February 28, 2021
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal researcher: Claudio Shyinti Kiminami
• Grantee: Gustavo Bertoli
• Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 13/05987-8 - Processing and characterization of amorphous, metastable and nano-structured metallic alloys, AP.TEM

Abstract

Multiprincipal, complex and concentrated, medium and/or high entropy alloys are different nomenclatures used for a new class of alloys that do not have a main element. Although hundreds of compositions have been produced to date, the compositional field of these alloys still remain mostly unexplored, especially regarding non-equiatomic compositions. Several compositions with superior properties compared to conventional alloys were discovered, among these, a series of alloys with excellent combinations of strength and ductility should be noted. The medium entropy equiatomic Cr33Co33Ni33 alloy is among the materials with highest fracture toughness ever produced, this is mostly attributed to the twinning induced plasticity (TWIP) deformation mechanism. Recent studies show that adjacent compositions can be even tougher, especially when the Cr content is increased. When more Co is added, the deformation mechanism switches to transformation induced plasticity (TRIP). In this study, the phase equilibria and mechanical properties of the non-equiatomic composition Cr40Co40Ni20 will be characterized in depth. The phase equilibria study will be performed by a combination of thermodynamic simulations with experimental studies, which will involve the production and characterization of samples heat treated at different temperatures. The mechanical behavior will be evaluated by tensile tests up to failure and by other tensile tests interrupted at fixed strain values. Samples with different grain sizes will be used in order to determine its effect on the mechanical properties and deformation mechanisms of the Cr40Co40Ni20 alloy. (AU)