Nanodomained Nickel Unite Nanocrystal Strength with Coarse-Grain Ductility

Wu, Xiaolei; Yuan, Fuping; Yang, Meng; Jiang, Ping; Zhang, Chuanxin; Chen, Liu; Wei, Yueguang; Ma, Evan

doi:10.1038/srep11728

Cited by 96 publications

(58 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ductility is measured under tensile loading either as total elongation to failure or as uniform elongation. The decrease in ductility with increasing strength is often observed because i) high strength metals often have low strain hardening rate, as in the case of cold worked metals and nanostructured metals [1,3e7]; ii) according to the Consid ere criterion, a high-strength metal would need a higher strain hardening rate to reach the same uniform elongation as that of a lowstrength metal [8,10].…”

Section: Introductionmentioning

confidence: 99%

Combining gradient structure and TRIP effect to produce austenite stainless steel with high strength and ductility

et al. 2016

View full text Add to dashboard Cite

a b s t r a c tWe report a design strategy to combine the benefits from both gradient structure and transformationinduced plasticity (TRIP). The resultant TRIP-gradient steel takes advantage of both mechanisms, allowing strain hardening to last to a larger plastic strain. 304 stainless steel sheets were treated by surface mechanical attrition to synthesize gradient structure with a central coarse-grained layer sandwiched between two grain-size gradient layers. The gradient layer is composed of submicron-sized parallelepiped austenite domains separated by intersecting ε-martensite plates, with increasing domain size along the depth. Significant microhardness heterogeneity exists not only macroscopically between the soft coarse-grained core and the hard gradient layers, but also microscopically between the austenite domain and ε-martensite walls. During tensile testing, the gradient structure causes strain partitioning, which evolves with applied strain, and lasts to large strains. The g / a 0 martensitic transformation is triggered successively with an increase of the applied strain and flow stress. Importantly, the gradient structure prolongs the TRIP effect to large plastic strains. As a result, the gradient structure in the 304 stainless steel provides a new route towards a good combination of high strength and ductility, via the co-operation of both the dynamic strain partitioning and TRIP effect.

show abstract

Section: Introductionmentioning

confidence: 99%

Combining gradient structure and TRIP effect to produce austenite stainless steel with high strength and ductility

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Ultrafine-grained (UFG) and nanostructured metals can be many times stronger than their conventional coarse-grained (CG) counterparts (1)(2)(3)(4)(5), but low ductility is a roadblock to their practical applications. The low ductility is primarily due to their low strain hardening (6)(7)(8)(9)(10)(11)(12), which is caused by their small grain sizes. To further exacerbate the problem, their high strengths require UFG metals to have even higher strain hardening than weaker CG metals to maintain the same ductility according to the Considère criterion.…”

mentioning

confidence: 99%

Heterogeneous lamella structure unites ultrafine-grain strength with coarse-grain ductility

Yang

Yuan

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

1,437

451

View full text Add to dashboard Cite

Grain refinement can make conventional metals several times stronger, but this comes at dramatic loss of ductility. Here we report a heterogeneous lamella structure in Ti produced by asymmetric rolling and partial recrystallization that can produce an unprecedented property combination: as strong as ultrafine-grained metal and at the same time as ductile as conventional coarse-grained metal. It also has higher strain hardening than coarse-grained Ti, which was hitherto believed impossible. The heterogeneous lamella structure is characterized with soft micrograined lamellae embedded in hard ultrafine-grained lamella matrix. The unusual high strength is obtained with the assistance of high back stress developed from heterogeneous yielding, whereas the high ductility is attributed to back-stress hardening and dislocation hardening. The process discovered here is amenable to large-scale industrial production at low cost, and might be applicable to other metal systems.back-stress hardening | heterogeneous lamella structure | ductility | strength | strain partitioning S trong or ductile? For centuries engineers have been forced to choose one of them, not both as they would like to. This is because a material is either strong or ductile but rarely both at the same time. High strength is always desirable, especially under the current challenge of energy crisis and global warming, where stronger materials can help by making transportation vehicles lighter to improve their energy efficiency. However, good ductility is also required to prevent catastrophic failure during service.Grain refinement has been extensively explored to strengthen metals. Ultrafine-grained (UFG) and nanostructured metals can be many times stronger than their conventional coarse-grained (CG) counterparts (1-5), but low ductility is a roadblock to their practical applications. The low ductility is primarily due to their low strain hardening (6-12), which is caused by their small grain sizes. To further exacerbate the problem, their high strengths require UFG metals to have even higher strain hardening than weaker CG metals to maintain the same ductility according to the Considère criterion. This makes it appear hopeless for UFG materials to have high ductility and it has been taken for granted that they are super strong but inevitably much less ductile than their CG counterparts. Microstructure of Heterogeneous Lamella StructureHere we report that a previously unidentified heterogeneous lamella (HL) structure possesses both the UFG strength and the CG ductility, which to our knowledge has never been realized before. The HL structure was produced by asymmetric rolling (13, 14) and subsequent partial recrystallization (see Materials and Methods for details). The asymmetric rolling elongated the initial equiaxed grains (Fig. 1A) into a lamella structure (Fig. 1B), which is heterogeneous with some areas having finer lamella spacing than others. This was due to the variation of slip systems and plastic strain in grains with different initial orientation ...

show abstract

“…As a result, the appearance of early necking can induce the materials′ fracture, which can be attributed to the lack of limitation to plastic instability. A variety of strategies, such as the multi-and bimodal microstructures, nanolaminated structure, and gradient nanostructure, aimed at improving the poor ductility of NC and UFG materials have been reported [8,18,19]. Among them, the bimodal grain size distribution microstructure, in which volume fraction of micron-sized grains are introduced into the NC and UFG matrix, is considered as an efficient strategy.…”

Section: Introductionmentioning

confidence: 99%

Enhanced tensile ductility and strength of electrodeposited ultrafine-grained nickel with a desired bimodal microstructure

Qian

Liu

et al. 2017

Materials Science and Engineering: A

Self Cite

View full text Add to dashboard Cite

A B S T R A C TThis work aims to use surfactant-assisted direct current electrodeposition technique to prepare four types of bimodal nickel, under different current densities. Bimodal Ni is obtained with different grain size and spatial distribution of CG and UFG areas showing a big disparity in mechanical properties. As a result of small population of coarse-grained surrounded by quite a lot of ultrafine-grained forming a unique shell-and-core bimodal structure, bimodal one present the best comprehensive mechanical properties with an ultrahigh tensile strength (~847 MPa) and a considerable plastic strain (~16.7%). Deformation initial, bimodal structures display more positive strain hardening to meaningful strains than unimodal structure of UFG and CG. Particularly bimodal one work-hardening rate is the highest thanks to its structure (UFG occupy 76.7% in total number fraction) and the distribution of growth twins. Growth twins in this article are referred to Σ3(111) coherent twins playing an important role in improving high strength, enhancing uniform plastic deformation ability.

show abstract

Nanodomained Nickel Unite Nanocrystal Strength with Coarse-Grain Ductility

Cited by 96 publications

References 44 publications

Combining gradient structure and TRIP effect to produce austenite stainless steel with high strength and ductility

Combining gradient structure and TRIP effect to produce austenite stainless steel with high strength and ductility

Heterogeneous lamella structure unites ultrafine-grain strength with coarse-grain ductility

Enhanced tensile ductility and strength of electrodeposited ultrafine-grained nickel with a desired bimodal microstructure

Contact Info

Product

Resources

About