Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys

Shi, Peijian; Li, Runguang; Li, Yang; Wen, Yuebo; Zhong, Yunbo; Ren, Weili; Shen, Zhe; Zheng, Tianxiang; Peng, Jianchao; Li, Xue; Hu, Pengfei; Min, Na; Zhang, Yong; Ren, Yang; Liaw, Peter K.; Raabe, Dierk; Wang, Yandong

doi:10.1126/science.abf6986

Cited by 409 publications

(80 citation statements)

References 61 publications

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“…Eutectic alloys have achieved a dominant position in the history of human civilization 1 , 2 , e.g., cast irons in agricultural society 3 , casting aluminum alloys in modern industry 4 , and eutectic high-entropy alloys (EHEAs) in advanced metallic materials 5 – 8 . Excellent castability, free of segregations/defects, and self-generated dual phases make eutectic alloys significantly advantaged in low-cost mass-production and balanced strength-ductility combination 9 , 10 .…”

Section: Introductionmentioning

confidence: 99%

Phase-selective recrystallization makes eutectic high-entropy alloys ultra-ductile

et al. 2022

Nat Commun

102

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Excellent ductility is crucial not only for shaping but also for strengthening metals and alloys. The ever most widely used eutectic alloys are suffering from the limited ductility and losing competitiveness among advanced structural materials. Here we report a distinctive concept of phase-selective recrystallization to overcome this challenge for eutectic alloys by triggering the strain hardening capacity of the duplex phases completely. We manipulate the strain partitioning behavior of the two phases in a eutectic high-entropy alloy (EHEA) to obtain the phase-selectively recrystallized microstructure with a fully recrystallized soft phase embedded in the skeleton of a hard phase. The resulting microstructure fully releases the strain hardening capacity in EHEA by eliminating the weak boundaries. Our phase-selectively recrystallized EHEA achieves a high ductility of ∼35% uniform elongation with true stress of ∼2 GPa. This concept is universal for various duplex alloys with soft and hard phases and opens new frontiers for traditional eutectic alloys as high-strength metallic materials.

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Section: Introductionmentioning

confidence: 99%

Phase-selective recrystallization makes eutectic high-entropy alloys ultra-ductile

et al. 2022

Nat Commun

102

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“…S7). These high-density microcracks act effectively to release local concentrated stresses and improve plasticity ( 38 , 39 ).…”

Section: Resultsmentioning

confidence: 99%

Metal-carbide eutectics with multiprincipal elements make superrefractory alloys

Wei

Shen

et al. 2022

Sci. Adv.

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Materials with excellent high-temperature strength are now sought for applications in hypersonics, fusion reactors, and aerospace technologies. Conventional alloys and eutectic multiprincipal-element alloys (MPEAs) exhibit insufficient strengths at high temperatures due to low melting points and microstructural instabilities. Here, we report a strategy to achieve exceptional high-temperature microstructural stability and strength by introducing eutectic carbide in a refractory MPEA. The synergistic strengthening effects from the multiprincipal-element mixing and strong dislocation blocking at the interwoven metal-carbide interface make the eutectic MPEA not only have outstanding high-temperature strength (>2 GPa at 1473 K) but also alleviate the room-temperature brittleness through microcrack tip blunting by layered metallic phase. This strategy offers a paradigm for the design of the next-generation high-temperature materials to bypass the low–melting point limitation of eutectic alloys and diffusion-dominated softening in conventional superalloys.

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“…Further plastic deformation results in the synergistic deformation of both hard and soft lamellae, with soft FCC lamellae bearing a higher strain, leading to the more substantial HDI hardening effect. Moreover, the aligned lamellar structure and ductile FCC matrix can delay crack propagation and coalescence, thereby delaying the onset of global necking (Shi et al, 2019;Shi et al, 2021).…”

Section: Eutectic Structurementioning

confidence: 99%

Mechanical Properties and Deformation Mechanisms of Heterostructured High-Entropy and Medium-Entropy Alloys: A Review

2022

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Recently, heterostructured (HS) materials, consisting of hard and soft zones with dramatically different strengths, have been developed and received extensive attention because they have been reported to exhibit superior mechanical properties over those predicted by the rule of mixtures. Due to the accumulation of geometrically necessary dislocations during plastic deformation, a back stress is developed in the soft zones to increase the yield strength of HS materials, which also induce forward stress in the hard zones, and a global hetero-deformation induced (HDI) hardening to retain ductility. High-entropy alloys (HEAs) and medium-entropy alloys (MEAs) or multicomponent alloys usually contain three or more principal elements in near-equal atomic ratios and have been widely studied in the world. This review paper first introduces concepts of HS materials and HEAs/MEAs, respectively, and then reviewed emphatically the mechanical properties and deformation mechanisms of HS HEAs/MEAs. Finally, we discuss the prospect for industrial applications of the HS HEAs and MEAs.

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Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys

Cited by 409 publications

References 61 publications

Phase-selective recrystallization makes eutectic high-entropy alloys ultra-ductile

Phase-selective recrystallization makes eutectic high-entropy alloys ultra-ductile

Metal-carbide eutectics with multiprincipal elements make superrefractory alloys

Mechanical Properties and Deformation Mechanisms of Heterostructured High-Entropy and Medium-Entropy Alloys: A Review

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