High entropy alloys of Al-Co-Cr-Fe-Ni have been developed for high-temperature applications due to their high melting points,superior microstructural stability,and the ability to form a protective oxide scale on the s...High entropy alloys of Al-Co-Cr-Fe-Ni have been developed for high-temperature applications due to their high melting points,superior microstructural stability,and the ability to form a protective oxide scale on the surface.This paper presents the results of research on the isothermal oxidation of the Al0.5CoCrFeNi alloy at temperatures of 900,1000,and 1100 ℃ for 2,16,and 40 h.A series of experiments were conducted to investigate the microstructural stability and oxidation behavior of the alloy.During oxidation,the alloy forms various oxides,including Fe_(2)O_(3),Co3O_(4),spinel of Cr_(2)NiO_(4),Cr_(2)O_(3),and Al_(2)O_(3),as well as AlN.It was found that the oxidation behavior of the alloy is closely related to that of the general medium entropy M-Cr-Al system(M=Fe,Ni,Al).The oxidation kinetics of the alloy follow a parabolic rate law with an activation energy of 195.7 kJ/mol.The instability of the microstructure of the alloy is indicated by the spheroidization of the B2 phase due to thermal stress occurring at the A1/B2 phase interface,in addition to a decrease in its volume fraction.These microstructural changes result in a decrease in the alloy's hardness.展开更多
基金support from Riset dan Inovasi untuk Indonesia Maju(RIIM)Gelombang 2–National Research and Innovation Agency(BRIN)and Educational Fund Management Institution(LPDP)(78/IV/KS/11/2022 and 834/IT1.B07/KS.00/2022)
文摘High entropy alloys of Al-Co-Cr-Fe-Ni have been developed for high-temperature applications due to their high melting points,superior microstructural stability,and the ability to form a protective oxide scale on the surface.This paper presents the results of research on the isothermal oxidation of the Al0.5CoCrFeNi alloy at temperatures of 900,1000,and 1100 ℃ for 2,16,and 40 h.A series of experiments were conducted to investigate the microstructural stability and oxidation behavior of the alloy.During oxidation,the alloy forms various oxides,including Fe_(2)O_(3),Co3O_(4),spinel of Cr_(2)NiO_(4),Cr_(2)O_(3),and Al_(2)O_(3),as well as AlN.It was found that the oxidation behavior of the alloy is closely related to that of the general medium entropy M-Cr-Al system(M=Fe,Ni,Al).The oxidation kinetics of the alloy follow a parabolic rate law with an activation energy of 195.7 kJ/mol.The instability of the microstructure of the alloy is indicated by the spheroidization of the B2 phase due to thermal stress occurring at the A1/B2 phase interface,in addition to a decrease in its volume fraction.These microstructural changes result in a decrease in the alloy's hardness.
