Presentation Title

Effect of Aluminum Content on the Hot Corrosion of High Entropy Alloys

Faculty Mentor

Dr. Vilupanur Ravi, Chemical and Materials Engineering, Cal Poly Pomona

Start Date

17-11-2018 1:45 PM

End Date

17-11-2018 2:00 PM

Location

C302

Session

Oral 3

Type of Presentation

Oral Talk

Subject Area

engineering_computer_science

Abstract

High entropy alloys (HEAs) have recently re-emerged as a new class of alloys with the potential to be utilized in advanced engineering applications. They exhibit an attractive combination of wear resistance, hardness and high temperature strength coupled with relatively low densities. Turbine blades are one of many potential applications that are being explored for HEAs. Gas turbines operating in the 650-900°C range in marine environments, can be subjected to accelerated corrosion beneath a thin molten eutectic salt film consisting of NaCl and Na2SO4 (Type II hot corrosion). This study builds on our earlier studies of the hot corrosion behavior of an equimolar AlCoCrFeNi high entropy alloy with relatively high aluminum content. The questions raised by our earlier work led to the current study in which the aluminum content of this alloy was varied. The AlxCoCrFeNi high entropy alloy was produced at various aluminum contents (x=0, 0.3, 0.6) and tested in a range of 700-800°C under a molten NaCl-Na2SO4 eutectic salt mixture. In situ DC electrochemical testing techniques were utilized to characterize the corrosion behavior of these alloys. The morphology of attack was studied using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Aluminum provides the HEA with protection against corrosion at 700°C. The same HEA at 800°C performed better with no aluminum content when compared to minimal aluminum content at 0.3 molar ratio; 0.6 aluminum molar ratio performed on par with no aluminum.

Summary of research results to be presented

In this study, the AlxCoCrFeNi high entropy alloy was produced at various aluminum contents (x=0, 0.3, 0.6) and tested at 700°C and 800°C under a molten NaCl-Na2SO4 eutectic salt mixture. In situ DC electrochemical testing techniques were utilized to characterize the corrosion behavior of these alloys. The corrosion rate at 700°C for the high entropy alloy decreases with increasing aluminum content. The same HEA at 800°C performed better with no aluminum content when compared to minimal aluminum content at 0.3 molar ratio; 0.6 aluminum molar ratio performed on par with no aluminum.

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Nov 17th, 1:45 PM Nov 17th, 2:00 PM

Effect of Aluminum Content on the Hot Corrosion of High Entropy Alloys

C302

High entropy alloys (HEAs) have recently re-emerged as a new class of alloys with the potential to be utilized in advanced engineering applications. They exhibit an attractive combination of wear resistance, hardness and high temperature strength coupled with relatively low densities. Turbine blades are one of many potential applications that are being explored for HEAs. Gas turbines operating in the 650-900°C range in marine environments, can be subjected to accelerated corrosion beneath a thin molten eutectic salt film consisting of NaCl and Na2SO4 (Type II hot corrosion). This study builds on our earlier studies of the hot corrosion behavior of an equimolar AlCoCrFeNi high entropy alloy with relatively high aluminum content. The questions raised by our earlier work led to the current study in which the aluminum content of this alloy was varied. The AlxCoCrFeNi high entropy alloy was produced at various aluminum contents (x=0, 0.3, 0.6) and tested in a range of 700-800°C under a molten NaCl-Na2SO4 eutectic salt mixture. In situ DC electrochemical testing techniques were utilized to characterize the corrosion behavior of these alloys. The morphology of attack was studied using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Aluminum provides the HEA with protection against corrosion at 700°C. The same HEA at 800°C performed better with no aluminum content when compared to minimal aluminum content at 0.3 molar ratio; 0.6 aluminum molar ratio performed on par with no aluminum.