Phase separation in equiatomic AlCoCrFeNi high-entropy alloy

On the Path to Optimizing the Al-Co-Cr-Cu-Fe-Ni-Ti High Entropy Alloy Family for High Temperature Applications

“…Specimens for 3D-AP observations were first cut from a foil into rods of 0.25ˆ0.25ˆ10 mm 3 and then thinned down to a tip diameter of about 50 nm in two steps, using a final polishing solution of 98% butoxyethanol and 2% perchloric acid and a final voltage of 3 V. More detailed information can be found in [15,17]. The 3D-AP used in this study is a TAP (tomographic atom probe) by CAMECA (Genevilliers, France).…”

“…Thus, in this work the microstructural evolution and, on a second level some mechanical properties, have been compared, starting from the "classic" equiatomic AlCoCrCuFeNi [11][12][13][14] alloy over AlCoCrFeNi [15,16] [19] to the optimized Al 10 Co 25 Cr 8 Fe 15 Ni 36 Ti 6 alloy (all at.%, or, in the case of AlCoCrFeNi and AlCoCrCuFeNi, mole fractions, as will be the case in the rest of the manuscript). For all six alloys the optimum heat treatment, which leads to the morphology closest to the one of CMSX-4, has been retained and the samples have been investigated by optical microscopy, transmission electron microscopy (TEM), three dimensional atom probe (3D-AP), Vickers hardness measurements and tensile or compression tests.…”

High-Entropy Alloys: A Critical Review

“…This is evidenced by detailed transmission electron microscopy (TEM) and atomic probe analysis. [21,31,32] Thirdly, in HEAs similar disordered and ordered versions of the same base structure often co-exist. [8,[33][34][35] For example, coexistence of BCC and ordered BCC (B2) phases was frequently reported.…”

“…This is not sufficient for unraveling the structure-property relationship in HEAs because all detailed microstructure observations reveal the existence of nano-sized or even atomic-scale precipitations and/or decompositions. [21,31,32,34,35,98,142] More tests aimed at prolonged service and/or high-temperature applications are also required. These include but are not limited to: fatigue behavior, [67] oxidation resistance, [50,51,104] structural stability, and creep behavior.…”

Influence of Annealing on the Microstructures and Oxidation Behaviors of Al8(CoCrFeNi)92, Al15(CoCrFeNi)85, and Al30(CoCrFeNi)70 High-Entropy Alloys

“…This particular alloy system is ideal for a fundamental oxidation study since it contains both Al and Cr, which are known to produce protective Cr 2 O 3 and/or Al 2 O 3 scales [30]. Additionally, the AlCoCrFeNi system is one of the most thoroughly investigated to date [1,4,10,14,[31][32][33][34][35][36][37][38][39][40][41][42][43]. This paper will systematically report the influence of annealing on the microstructures and active oxidation mechanisms.…”