Correlating Strength and Hardness of High‐Entropy Alloys

Tian, Yanzhong; Li, Linlin; Li, Jingjing; Yang, Yang; Li, Song; Qin, Gaowu

doi:10.1002/adem.202001514

Cited by 34 publications

(8 citation statements)

References 101 publications

(171 reference statements)

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“…This effect implies the possibility of returning the lattice to its original state (before irradiation) in samples irradiated with ions by neutralizing radiation-induced defects. By selecting the correct value of the operating temperature, for example, it is possible to achieve a permanent restoration of the HEA structure during irradiation using the “self-healing effect” directly in the process of operation [ 21 , 22 , 23 , 24 , 25 , 26 ]. In the NiCoFeCrMn alloy, the migration energies of interstitial atoms and vacancies differ little or even intersect [ 27 , 28 ], which accelerates recombination and increases the possibility of defect annihilation, reducing the number of defects.…”

Section: Introductionmentioning

confidence: 99%

Composition and Structure of NiCoFeCr and NiCoFeCrMn High-Entropy Alloys Irradiated by Helium Ions

et al. 2023

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High-entropy alloys (HEAs) have prospects for use as nuclear structural materials. Helium irradiation can form bubbles deteriorating the structure of structural materials. The structure and composition of NiCoFeCr and NiCoFeCrMn HEAs formed by arc melting and irradiated with low-energy 40 keV He2+ ions and a fluence of 2 × 1017 cm−2 have been studied. Helium irradiation of two HEAs does not change the elemental and phase composition, and does not erode the surface. Irradiation of NiCoFeCr and NiCoFeCrMn with a fluence of 5 × 1016 cm−2 forms compressive stresses (−90 … −160 MPa) and the stresses grow over −650 MPa as fluence increases to 2 × 1017 cm−2. Compressive microstresses grow up to 2.7 GPa at a fluence of 5 × 1016 cm−2, and up to 6.8 GPa at 2 × 1017 cm−2. The dislocation density rises by a factor of 5–12 for a fluence of 5 × 1016 cm−2, and by 30–60 for a fluence of 2 × 1017 cm−2. Stresses and dislocation density in the HEAs change the most in the region of the maximal damage dose. NiCoFeCrMn has higher macro- and microstresses, dislocation density, and a larger increase in their values, with an increasing helium ion fluence compared to NiCoFeCr. NiCoFeCrMn a showed higher radiation resistance compared to NiCoFeCr.

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Section: Introductionmentioning

confidence: 99%

Composition and Structure of NiCoFeCr and NiCoFeCrMn High-Entropy Alloys Irradiated by Helium Ions

et al. 2023

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“…In general, hardness reflects the plasticity resistance of a material, and hardness was proportional to strength [ 22 ]. In previous studies, the average microhardness of the 7075 aluminum alloy matrix was

HV 0.2 .…”

Section: Resultsmentioning

confidence: 99%

Effect of Reticulate Unit Spacing on Microstructure and Properties of Biomimetic 7075 Aluminum Alloy by Laser Cladding

et al. 2023

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In the context of energy conservation and emission reduction, more and more attention has been paid to the development of lightweight metal materials with both high strength and high toughness. Inspired by the non-smooth surface of natural organisms, a biomimetic surface with various spacing reticulate units of 7075 aluminum alloys was modified by laser cladding. The microstructure, microhardness and tensile properties of the various spacing units with CeO2-SiC-Ni60 were studied. The finer microstructure and the higher microhardness of various spacing units in comparison with that of 7075 aluminum alloys were obtained, no matter the strip-like treated region or the cross-junction region. Moreover, the best combination of strength and toughness of the biomimetic sample with 2.5 mm spacing reticulate unit was discussed. Finally, by combining the microstructure, XRD phase change, thermal gradient effect, thermal expansion coefficient difference and hard phase strengthening mechanism, it was concluded that the 2.5 mm spacing reticulate unit had the best ability to inhibit crack propagation, and the dispersive hard phases of Al3Ni2 and SiC played a major role in stress release of the matrix.

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“…For a wide range of alloys, a ratio of 1:3 between yield strength and Vickers hardness was observed by various researches as reported in the study by Tian et al, [ 32 ] representing a linear relationship between hardness and tensile strength. Considering that, this relationship is only a rough approximation and might differ especially for intermetallic alloys, it still suggests that the observed increase in hardness by 230% also indicates a tremendous increase in tensile strength.…”

Section: Discussionmentioning

confidence: 95%

Multimaterial Additive Manufacturing of Graded Laves Phase Reinforced NiAlTa Structures by Means of Laser Metal Deposition

Müller¹,

Stellmacher

Riede

et al. 2021

Adv Eng Mater

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Recently, the additive manufacturing (AM) technology laser metal deposition (LMD) has gained a lot of attention for processing crack prone high temperature materials such as nickel‐based superalloys or intermetallics. A feasibility study on LMD of a graded transition from binary ß‐NiAl to Ni50Al42Ta8 is presented with the aim to show the possibility of manufacturing ß‐NiAl‐based structures with a spatially resolved microstructure and subsequently tailored mechanical properties. For achieving this, the alloys Ni50Al50 and Ni50Al42Ta8 are coinjected into the process zone and the powder feeding rates are adapted in a layerwise manner. Due to preheating temperatures of up to 1000 °C, the transition can be manufactured with high relative density and a low degree of cold cracking. Scanning electron microscopy of the transition zone shows the formation of a fine dendritic microstructure consisting of ß‐NiAl dendritic and NiAlTa interdendritic regions. Large area energy‐dispersive X‐ray analysis reveals a gradient in NiAlTa Laves phase content with increasing build height. The observed volume fraction of Laves phase corresponds well to reported values from cast ingots. Finally, hardness measurements along the build‐up direction show an increase in hardness from 300 HV0.1 to 680 HV0.1 indicating a tremendous increase in tensile strength.

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Correlating Strength and Hardness of High‐Entropy Alloys

Cited by 34 publications

References 101 publications

Composition and Structure of NiCoFeCr and NiCoFeCrMn High-Entropy Alloys Irradiated by Helium Ions

Composition and Structure of NiCoFeCr and NiCoFeCrMn High-Entropy Alloys Irradiated by Helium Ions

Effect of Reticulate Unit Spacing on Microstructure and Properties of Biomimetic 7075 Aluminum Alloy by Laser Cladding

Multimaterial Additive Manufacturing of Graded Laves Phase Reinforced NiAlTa Structures by Means of Laser Metal Deposition

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