Oxide dispersion strengthened CoCrFeNiMn high-entropy alloy

Hadraba, Hynek; Chlup, Zdeněk; Dlouhý, A.; Dobeš, F.; Roupcová, Pavla; Vilémová, Monika; Matějíček, Jiří

doi:10.1016/j.msea.2017.02.068

Cited by 144 publications

(48 citation statements)

References 29 publications

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“…A small volume of fine nano-crystalline Y-Ti oxides distributed within a large volume of the HEA matrix is below the XRD detection limit; thus, weak diffraction peaks of the oxides are not visible in the measured spectra. The presence of the Y-Ti oxides was, nevertheless, proved in the authors' previous study by TEM and EDS [16]. The literature reports that Y 2 TiO 5 and Y 2 Ti2O 7 are the most common oxides present in Y-Ti-doped alloys [23].…”

Section: Resultsmentioning

confidence: 84%

Phase, Composition and Structure Changes of CoCrNi-Based Concentrated Alloys Resulting from High Temperature Oxidation

et al. 2020

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In this work, CoCrNi, FeCoCrNi and CoCrFeMnNi concentrated alloys with a Y-Ti oxide particle dispersion were prepared by mechanical alloying and Spark Plasma Sintering. The alloy consists of an FCC Ni-based matrix with a Y-Ti oxide dispersion and additional phases of Cr23C6 and Cr2O3. The effect of Fe, Mn, and Y-Ti oxide particles on the formation of oxide scales and the composition of the adjacent CoCrNi and FeCoCrNi alloys was studied. It was found that alloys without Mn in their composition form a protective Cr2O3 scale. The Cr23C6 particles provide an alternative mechanism for balancing the chromium loss during the oxidation. Y and Ti from the oxide particles participate in the formation of the protective oxide scales. Fe promotes Y and especially Ti diffusion through the Cr2O3 scale, resulting in the formation of Ti-depleted regions in the alloy. The findings will serve for the further development of these new materials.

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Section: Resultsmentioning

confidence: 84%

Phase, Composition and Structure Changes of CoCrNi-Based Concentrated Alloys Resulting from High Temperature Oxidation

et al. 2020

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“…Two CoCrFeNiMn HEA alloys varying in the grain size distribution as a result of SPS compaction parameters were prepared. The alloy powder was prepared from pure powders of elements by ball milling process as described in detail elsewhere [7]. The compaction of the materials (hereafter HEA 5 and HEA 10) was conducted by the SPS technique with the consolidation temperature of 1150 • C for a dwell time of 5 and 10 min, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…A large variety of HEAs exists, but single-phase equiatomic five-element HEA Co-Cr-Fe-Mn-Ni, the so-called Cantor alloy, is one of the most studied [5]. The single-phase solid solution high-entropy alloys have a potential for solid solution hardening and if the single-phase fcc lattice structure is reached, a large number of slip systems ensures good ductility of the material [6][7][8][9]. Nevertheless, the experimental data about mechanical behaviour of this alloy type are still not fully understood and in some cases are controversial.…”

Section: Introductionmentioning

confidence: 99%

“…The preferential processing method of this type of HEA is some variant of casting usually followed by heat treatment [5,[8][9][10][11]. Also, powder metallurgy resulting in differences in the HEA microstructure as well as in the properties was used in [7,[12][13][14]. The microstructure of the cast alloys is rather coarse with the grain sizes range from tens to hundreds of micrometres.…”

Section: Introductionmentioning

confidence: 99%

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Fatigue Behaviour and Crack Initiation in CoCrFeNiMn High-Entropy Alloy Processed by Powder Metallurgy

Chlup

Fintová

Hadraba

et al. 2019

Metals

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Single-phase equiatomic five-element high entropy alloy CoCrFeMnNi was prepared by powder metallurgy. Two materials with ultra-fine-grained microstructure were prepared by spark plasma sintering (SPS) of ball-milled powder at two sintering times (5 and 10 min), assigned as HEA 5 and HEA 10, respectively. Basic microstructural and mechanical properties were evaluated. The median grain size of the microstructures was determined to be 0.4 and 0.6 µm for HEA 5 and HEA 10, respectively. The differences in the microstructure led to a significant change in strength and deformation characteristics evaluated at room temperature. The effect of cyclic loading was monitored by three-point bending fatigue test. The results show that even relatively small change in the microstructure causes a significant effect on fatigue life. The fatigue endurance limit was measured to be 1100 MPa and 1000 MPa for HEA 5 and HEA 10, respectively. The detailed fractographic analysis revealed that abnormally large grains, localised in the microstructure on the tensile loaded surface, were a typical fatigue initiation site. The formation of (nano) twins together with dislocation slips caused the crack nucleation because of the cyclic loading.

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“…Various studies undertaken have concluded that the absorption of REEs in the cladding materials system can potentially reduce the dilution rate, improve coating toughness, reduce cracking tendency, enhance corrosion resistance and augment bioactivity of bioceramic reimplants [18][19][20][21][22]. Inspired from the development of oxide dispersion strengthening (ODS) alloys, oxide particles, which act as effective pinning for grain boundaries and dislocations, were introduced into HEAs to improve their mechanical properties [23][24][25][26]. In addition, the reactive RE elements Y and Hf were doped into AlCoCrFeNi HEA by ingot metallurgy, which resulted in superior oxidation performance due to the beneficial REs-effects on the fast establishment of exclusive α-Al 2 O 3 scale in early oxidation stage [27].…”

Section: Introductionmentioning

confidence: 99%

Laser Cladding of Al0.5CoCrCuFeNiSi High Entropy Alloy Coating without and with Yttria Addition on H13 Steel

et al. 2020

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Al0.5CoCrCuFeNiSi high entropy alloy coating without and with a 1 wt.% Y2O3 addition was fabricated by laser cladding technique on H13 substrate. The results showed that the laser cladding coatings without and with Y2O3 addition consist of a mixture of body centered cubic (BCC) dendrites and face centered cubic (FCC) interdendrites. With the addition of Y2O3, the peaks of BCC dendrites in the coating shifted to leftwards, which is caused by the distortion of lattice due to the dissolution of Y with larger atomic radius. There exist cracks and porosities in the coating without Y2O3 addition. With Y2O3 addition, the cracks and porosities in the laser cladding coating were inhibited greatly. In addition, the microstructure of the coating with Y2O3 addition was refined due to the improving of the ratio of nucleation. The enhancement of properties, such as hardness, wear resistance and corrosion resistance, of the coating with Y2O3 addition came from the inhibition of cracks and porosities and the refinement of microstructure.

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Oxide dispersion strengthened CoCrFeNiMn high-entropy alloy

Cited by 144 publications

References 29 publications

Phase, Composition and Structure Changes of CoCrNi-Based Concentrated Alloys Resulting from High Temperature Oxidation

Phase, Composition and Structure Changes of CoCrNi-Based Concentrated Alloys Resulting from High Temperature Oxidation

Fatigue Behaviour and Crack Initiation in CoCrFeNiMn High-Entropy Alloy Processed by Powder Metallurgy

Laser Cladding of Al0.5CoCrCuFeNiSi High Entropy Alloy Coating without and with Yttria Addition on H13 Steel

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