Abstract:In the present work, low cycle fatigue (LCF) behavior of an equiatomic CoCrFeMnNi high entropy alloy (HEA) is correlated to the microstructural evolution at 550 °C. The fully reversed strain-controlled fatigue tests were conducted in air under strain amplitudes ranging from 0.2 to 0.8%. The measured cyclic stress response showed three distinct stages which include initial cyclic hardening followed by a quasi-stable cyclic response until failure. The rate and amount of cyclic hardening increased with the increa… Show more
“…Initially, grain-to-grain misorientations including plastic strain incompatibilities between grains, result in a significant increase in dislocation density close to the grain boundaries. Upon further cycling, as dislocations multiply and spread across grains, they interact (including activity of secondary slip) leading to cyclic hardening [14]. For CoCrNi, additional interactions between dislocations and SFs as well as SBs (that form concurrently) also contribute to the cyclic hardening.…”
Section: Fig 2e-f Provide Representative Overlaid Iq and Ipf Maps Of ...mentioning
confidence: 99%
“…However, engineering alloys are usually not only loaded monotonically in service but also cyclically. Few studies, concerning the fatigue properties of HEAs have been reported [14][15][16][17][18][19], where it was shown that CoCrFeMnNi demonstrates a higher low-cycle fatigue (LCF) resistance compared to common FCC steels [14,19]. Recently, Rackwitz et al [20] revealed a superior fatigue crack propagation resistance of CoCrNi compared to CoCrFeMnNi [21], especially at cryogenic temperatures, where the increased propensity of nanotwinning decreased the crack growth rate.…”
“…Initially, grain-to-grain misorientations including plastic strain incompatibilities between grains, result in a significant increase in dislocation density close to the grain boundaries. Upon further cycling, as dislocations multiply and spread across grains, they interact (including activity of secondary slip) leading to cyclic hardening [14]. For CoCrNi, additional interactions between dislocations and SFs as well as SBs (that form concurrently) also contribute to the cyclic hardening.…”
Section: Fig 2e-f Provide Representative Overlaid Iq and Ipf Maps Of ...mentioning
confidence: 99%
“…However, engineering alloys are usually not only loaded monotonically in service but also cyclically. Few studies, concerning the fatigue properties of HEAs have been reported [14][15][16][17][18][19], where it was shown that CoCrFeMnNi demonstrates a higher low-cycle fatigue (LCF) resistance compared to common FCC steels [14,19]. Recently, Rackwitz et al [20] revealed a superior fatigue crack propagation resistance of CoCrNi compared to CoCrFeMnNi [21], especially at cryogenic temperatures, where the increased propensity of nanotwinning decreased the crack growth rate.…”
“… Fig. 5 Graphical compilation of low-cycle fatigue data of high-entropy alloys at the temperature of T = 298 K and strain ratio of R = −1 27 – 34 . ( a ) Total strain amplitude.…”
Fatigue failure of metallic structures is of great concern to industrial applications. A material will not be practically useful if it is prone to fatigue failures. To take the advantage of lately emerged high-entropy alloys (HEAs) for designing novel fatigue-resistant alloys, we compiled a fatigue database of HEAs from the literature reported until the beginning of 2022. The database is subdivided into three categories, i.e., low-cycle fatigue (LCF), high-cycle fatigue (HCF), and fatigue crack growth rate (FCGR), which contain 15, 23, and 28 distinct data records, respectively. Each data record in any of three categories is characteristic of a summary, which is comprised of alloy compositions, key fatigue properties, and additional information influential to, or interrelated with, fatigue (e.g., material processing history, phase constitution, grain size, uniaxial tensile properties, and fatigue testing conditions), and an individual dataset, which makes up the original fatigue testing curve. Some representative individual datasets in each category are graphically visualized. The dataset is hosted in an open data repository, Materials Cloud.
“…Ten Cr x Mn 20 Fe 20 Co 20 Ni 40-x alloys ( x = 0, 5, 10, 14,16,18,20,22,24, and 26 at. %) were produced starting from pure elements (purity > 99.9 wt.%).…”
Section: Materials Processingmentioning
confidence: 99%
“…Due to its good malleability [13][14][15] , which made it the pioneering HEA to be thermomechanically processed and investigated in bulk form, and interesting mechanical properties at cryogenic temperatures, e.g. , excellent tensile properties [ 13 , 14 ], outstanding fracture toughness [2] , high resistance to lowcycle-fatigue [16][17][18] and fatigue crack propagation [ 19 , 20 ], it is one of the most studied HEAs of the last decade. The outstanding damage tolerance of the CrMnFeCoNi HEA is thought to result from its relatively low intrinsic stacking fault energy ( γ isf ≈ 30 mJ/m 2 , [ 21 , 22 ]) which promotes planar glide of dissociated dislocations [ 5 , 14 ], delays the onset of cross-slip [5] , and induces mechanical twinning [ 14 , 23 ], thereby resulting in sustained, high work hardening rate.…”
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