Microstructure, mechanical and corrosion behaviors of AlCoCuFeNi-(Cr,Ti) high entropy alloys

Abstract

The equimolar AlCoCuFeNi-(Cr,Ti) HEAs were synthesized by nonconsumable arc melting to investigate the effects of Cr and Ti on the mechanical and corrosion properties of the HEAs. The results showed that as-cast AlCoCuFeNi-(Cr,Ti) HEAs have a multi-phase microstructure, of which the solid-solution face-centered cubic (FCC), body-centered cubic (BCC) phases, and intermetallics can be observed. Ab initio molecular-dynamics (AIMD) simulations exhibit the existence of the preferred short-range ordering of Al-Ni, Co-Cr, Cr-Fe, and Ti-Co pairs in the AlCoCuFeNiCrTi liquid structure. The AIMD simulations are consistent with the experimental observation during solidification. The segregations and the FCC Cu-rich phase appear in the AlCoCuFeNiCrTi alloy, which is in agreement with AIMD calculations. The Cr addition to AlCoCuFeNi facilitates the formation of the BCC phases in the AlCoCuFeNiCr alloy, which can be explained by the larger Ω and smaller δ values. The addition of large Ti atoms facilitates the formation of the FCC phase, which is due to the fact that Ti will easily induce the breakdown of the BCC solid-solution of the AlCoCuFeNi alloy in terms of decreasing the Ω value and increasing the δ value. The Cr addition improves the corrosion resistance of AlCoCuFeNi alloys.

Synthesis and characterization of multicomponent (CrNbTaTiW)C films for increased hardness and corrosion resistance

“…For all films the cubic B1 structure has been used for indexing. The NBD patterns of NEC300 prove that columns in two different crystal orientations [1][2][3][4][5][6][7][8][9][10] and [0−11] coexist. By combining these two diffraction patterns, all reflections in the SAED pattern of NEC300 can be identified, as shown in the overlayed pattern.…”

“…By combining these two diffraction patterns, all reflections in the SAED pattern of NEC300 can be identified, as shown in the overlayed pattern. The overlap of the 111-reflections for the [1][2][3][4][5][6][7][8][9][10] and [0-11] zone axes indicates that the two different orientations share a common (111) lattice plane. Since there is space between the single columns, no atomically close twin boundaries between the single columns are expected.…”

“…Using this approach, most reflections in the SAED could be identified as depicted in the overlay. For NEC600, a dense grain structure with small domains is observed and therefore a high twin boundary density is expected in which the dominant [1][2][3][4][5][6][7][8][9][10] and [0-11] twin zone axes share a common (111) lattice plane. The SAED pattern of the TaWC300 film can be indexed with the zone axis as depicted in the simulated diffraction pattern and the according overlay.…”

“…The results show that incorporation of low amounts of carbon results in an increase in strength due to precipitation and grain boundary hardening. While bulk refractory high entropy alloys have been studied in detail by experimental [6][7][8][9][10][11] and computational [12][13][14] material science, there are only a few studies published on the addition of carbon to HEAs based on strong carbide formers such as the early transition metal in group 4 and 5 [5,15,16]. Braic et al have shown that (TiZrNbHfTa)C with a B1 structure with C in the octahedral sites can be synthesised by co-sputtering in a reactive atmosphere [15].…”

CoCrFeMnNi high‐entropy alloy powder with excellent corrosion resistance and soft magnetic property prepared by gas atomization method

“…Recently, the corrosion behaviors of high-entropy alloys under aqueous conditions have been extensively evaluated on numerous systems, such as CuZrY/AlTiHf [41], CoCrFeNi(W 1-x Mo x ) [27], Al 2 CoCrCuFeNiTi x [42], Al x CoCrFeNi [43] and AlCoCuFeNi-(Cr,Ti) [44]. Like stainless steels, CoCrFeMnNi high-entropy alloy is expected to be corrosion-resistant due to the containment of passivating element chromium, which facilitates the formation of protective passive layer.…”