Re-Melting Behaviour and Wear Resistance of Vanadium Carbide Precipitating Cr27.5Co14Fe22Mo22Ni11.65V2.85 High Entropy Alloy

Abstract

High entropy alloys (HEAs) are among of the most promising new metal material groups. The achievable properties can exceed those of common alloys in different ways. Due to the mixture of five or more alloying elements, the variety of high entropy alloys is fairly huge. The presented work will focus on some first insights on the weldability and the wear behavior of vanadium carbide precipitation Cr27.5Co14Fe22Mo22Ni11.65V2.85 HEA. The weldability should always be addressed in an early stage of any alloy design to avoid welding-related problems afterwards. The cast Cr27.5Co14Fe22Mo22Ni11.65V2.85 HEA has been remelted using a TIG welding process and the resulting microstructure has been examined. The changes in the microstructure due to the remelting process showed little influence of the welding process and no welding-related problems like hot cracks have been observed. It will be shown that vanadium carbides or vanadium-rich phases precipitate after casting and remelting in a two phased HEA matrix. The hardness of the as cast alloy is 324HV0.2 and after remelting the hardness rises to 339HV0.2. The wear behavior can be considered as comparable to a Stellite 6 cobalt base alloy as determined in an ASTM G75 test. Overall, the basic HEA design is promising due to the precipitation of vanadium carbides and should be further investigated.

Wire and Arc Additive Manufacturing of a CoCrFeMoNiV Complex Concentrated Alloy Using Metal-Cored Wire—Process, Properties, and Wear Resistance

“…The shown alloy composition has been chosen to promote the formation of vanadium carbide. This precipitation has been shown in previous studies for cast specimen [34]. However, in this case, a formation of carbide has not been observed.…”

“…An initial characterization of the properties of the additively manufactured CCA regarding the mechanical-technological properties together with a first comparison of the wear resistance completes the work. The used composition is based on the compositions given in [34] and has been adjusted to allow the manufacturing of the metal-cored wire with a diameter of 2.4 mm.…”

“…A sample was moved cyclic under a defined load of 22.24 N in an abrasive suspension against chloroprene rubber at a speed of 20 m/min, Figure 3. This test has also been used in [34,41].…”

“…Figure 11 shows the loss of material in the G75 "Miller" test compared to the cast alloy used in [34], and two conventional hardfacing alloys. The less material that is removed from the specimens, the better they are suited as a wear protection system against three-body abrasive wear.…”

Future Trends in Advanced Materials and Processes

“…The effects of Niobium and Molybdenum on the microstructures and corrosion properties of high-entropy CrFeCoNiNb x Mo x and CrFeCoNiNb x Mo 1−x alloys were investigated [ 5 ] by preparing in arc melting equipment under an argon atmosphere. Together with growing Nb and Mo percentages, it will increase the hardness of the alloys because of formation of the hexagonal close packing phase of the solid solution [ 6 ]. An interesting approach was to re-melt using a TIG welding process and to determine the behavior and wear resistance of Vanadium carbide precipitating Cr 27.5 Co 14 Fe 22 Mo 22 Ni 11.65 V 2.85 High Entropy Alloy (HEA).…”