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Study of the precipitation hardening behavior of the Ni35Cr29.5Co29.5Nb2.5Ti0.7Al2.8 multicomponent alloy

Grant number: 19/22590-0
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): December 01, 2019
Field of knowledge:Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
Principal Investigator:Francisco Gil Coury
Grantee:Larissa Bitencourt Salvador
Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil


Multicomponent or high entropy alloys are a new class of alloys in which the main feature is that they do not have a main element. Among the multicomponent alloys already produced, the CrCoNi face centered cubic (FCC) single-phase alloys are among the toughest materials ever discovered. Precipitation hardening is an important strengthening mechanism in metals, in particular, small additions of Ti and Al in multicomponent CrCoNi FCC alloys tend to generate fine and coherent precipitates that substantially increase the strength of these alloys. Through thermodynamic calculations, a CrCoNi composition with small additions of Nb, Ti and Al (Ni35Cr29.5Co29.5Nb2.5Ti0.7Al2.8) was selected for this study. The addition of Nb targets the formation of gama' and gama'' precipitates, similar to those formed in Inconel 718 alloy, widely used in the aeronautical industry, but with the tougher CrCoNi matrix. A preliminary study presented here shows that this alloy has high potential to actually exhibit this precipitation hardening mechanism. In this study, ingots of this alloy will be produced, they will be homogenized and aged at two temperatures for different times. Precipitation hardening curves will be determined at the two different temperatures. Samples under selected conditions will be characterized by X-ray diffraction and scanning electron microscopy. The results will be analyzed to understand the potential of this alloy from a mechanical properties standpoint. (AU)