Calphad-assisted design of the Al-Co-Cr-Fe-Ni multiprincipal component alloys with high strength and high ductility

Abstract

Multiprincipal component alloys also known as high-entropy alloys are a new concept of alloys that breaks through the limitation of traditional alloy design which is usually based on one or at most two key elements and uses multiple principal elements to form alloys In this study the Al-Co-Cr-Fe-Ni system was used as the research object The CALPHAD approach was used to predict the phase formation and understand the impact of each element It’s hoped that CALPHAD can be used to find the correlation between alloy composition phase volume fraction and mechanical properties and design an Al-Co-Cr-Fe-Ni multiprincipal component alloy with high strength and high ductility The results show that in the Al-Co-Cr-Fe-Ni system Co and Ni are FCC phase stabilizers Cr is a BCC phase stabilizer Al is a B2 phase stabilizer and Fe is a neutral element CALPHAD can accurately simulate the reaction of Al-Co-Cr-Fe-Ni multi-principal component alloy during the solidification process and the phase type in the as-cast structure but the values of volume fraction are inaccurate with the experimental values By precipitating B2 and L12 from the FCC matrix the target alloy appears high strength and high ductility and its YS UTS and elongation are 470 MPa 790 MPa and 48% respectively

Date of Award	2019
Original language	English
Supervisor	Shih-kang Lin (Supervisor)