Influence of remelting on microstructure, hardness and corrosion behaviour of AlCoCrFeNiTi high entropy alloy

Abstract

High entropy alloys are a newly developed class of alloys, which tend to form a single solid solution or a mixture of solid solutions with simple crystal structures. These alloys possess excellent mechanical properties, thermal stability and corrosion resistance. In the present paper, an AlCoCrFeNiTi high entropy alloy was obtained by induction melting, and the influence of the remelting process on the mechanical and corrosion resistance characteristics of the alloy was investigated. Thus, optical and scanning electron microscopy revealed less phase segregation and a fine dendritic structure for the remelted alloy, while corrosion tests indicated that present alloy, in remelted state, has better corrosion resistance than as cast alloy and stainless steel. The Vickers microhardness measurements demonstrated an improvement of the alloy microhardness by remelting process due to the decrease in phase segregation and the increase in dendrite refinement level.

The Phase Composition and Microstructure of AlxCoCrFeNiTi Alloys for the Development of High-Entropy Alloy Systems

“…Only this peak clearly differs from the characteristic peaks of bcc (B2), since additional fcc peaks overlap with bcc (B2) peaks. This is in contrast to Soare et al [19] who assigned a peak at 26.2 • (Cu Kα radiation), corresponding the peak at 30.6 • (Co Kα radiation) to the complex cubic structure D0 3 . Nevertheless, a comparison to the referenced PDF 03-065-4682 indicates an fcc (A1) structure.…”

“…Table 4 A correlation in phase presence can be found between x = 0.2 and 0.8 alloys. The low aluminum content promotes the presence of the cc (A12) already mentioned by Soare et al [19]. With increasing aluminum content, the peak intensity decreases over x = 0.8 to absence for x = 1.5.…”

“…It seems that Zhang et al [15] detected this phase in the Al 0.5-1.0 CoCrFeNiTi system as well but did not assign it as the I43m space group; they assumed intermetallic phases of CoTi 2 and FeTi. Soare et al [19] found that the equimolar AlCoCrFeNiTi leads to the formation of two complex phases with D0 3 and the A12 structure type. The A12 structure is a centered cluster (cc) phase that pertains to the group of topologically close-packed structures (Frank-Kasper phases) characterized by brittleness and low formability.…”

Slurry Erosion Behavior of AlxCoCrFeNiTi0.5 High-Entropy Alloy Coatings Fabricated by Laser Cladding

“…Huang et al [10] prepared TiVCrAlSi HEA coatings on Ti-6Al-4V substrate by laser cladding and investigated the dry sliding wear behavior. The combination of the hard (Ti,V) 5 Si 3 phase and relatively ductile and tough BCC matrix improved the sliding wear resistance. Yue et al [11] studied the solidification behavior in laser cladding of AlCoCrCuFeNi high-entropy alloy on magnesium substrates using the Kurz-Giovanola-Trivedi and the Gaümann models.…”

“…It is important to develop new erosion-resistant materials. Recently, high-entropy alloys (HEAs) have attracted extensive attention due to their versatile combinations including high strength and hardness, good thermal stability, excellent corrosion and wear resistance [3][4][5][6]. These characteristics make them suitable candidates for structural and functional materials.…”