Wear and Corrosion Behaviour of Supersaturated Surface Layers in the High-Entropy Alloy Systems CrMnFeCoNi and CrFeCoNi

Abstract

The surface hardening of single-face-centred cubic (fcc)-phase CrMnFeCoNi and the manganese-free CrFeCoNi alloy was conducted using low-temperature nitrocarburisation. The microstructural investigations reveal the successful formation of a homogeneous diffusion layer with a thickness of approximately 16 µm. The interstitial solution of carbon and nitrogen causes an anisotropic lattice expansion. The increase in microhardness is in accordance to the graded concentration profile of the interstitial elements. Wear tests show a significantly enhanced resistance at different loads. The electrochemical tests reveal no deterioration in the corrosion resistance. The absence of precipitates is proven by microstructural investigations. The results prove the applicability of the concept of solution hardening by the formation of supersaturated solutions for the material group of high-entropy alloys. Hence, an increase of entropy with the consideration of lattice interstices provides new development approaches.

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

“…These materials are typically used in three-body abrasion, so the ASTM G75 “Miller Test” is used to characterize their wear properties. The wear resistance of these kinds of HEA are already of high interest and subject to studies in various alloy compositions [ 33 , 34 , 35 , 36 ]. The creation of an alloy-side basis for weldable wear-resistant high-entropy alloys is the aim of the investigations and the focus is on weldability.…”

CrMnFeCoNi high entropy alloys with carbon and nitrogen: mechanical properties, wear and corrosion resistance

“…In a FeNiMnAlCr non-equiatomic system, carbon increases the strength, and the ductility, and affects the work-hardening rate [9]. In CrMnFeCoNi and CrFeCoNi alloys, gas nitrocarburization has been applied in order to build layers below 20 m, and this has a direct impact on the hardness of the subsurface and the wear resistance [10]. In this same system, and by means of hot pressing sintering, nitrogen improves the strength of the alloy and reduces its ductility [11].…”

Strain‐Rate Sensitive Deformation Behavior under Tension and Compression of Al0.3CrFeCoNiMo0.2

“…[ 9,10 ] In particular, single‐phase, face‐centered cubic (FCC) CrMnFeCoNi and its derivatives are among the most studied HEAs. [ 11–20 ] To further improve the mechanical properties and strain hardening behavior of this alloy system, additional alloying elements are added. The addition of small amounts of one or more alloying elements can either maintain the single‐phase character of the material or affect the formation of additional intermetallic phases.…”