Obtaining Copper with Harmonic Structure for the Optimal Balance of Structure-Performance Relationship

Orlov, Dmitry; Fujiwara, Hiroshi; Ameyama, Kei

doi:10.2320/matertrans.mh201320

Cited by 72 publications

(36 citation statements)

References 16 publications

(10 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to improve the control over the microstructural characteristics, and thus properties, Ameyama and co‐workers recently proposed a novel approach based on the powder metallurgy route. Its peculiar features are: (i) the MM processing is optimized to induce heterogeneous structure in powder particles having CG and nano/UFG structures in their core and periphery, respectively; and (ii) the consolidation is optimized to preserve the heterogeneity.…”

Section: Quantitative Characteristics Of Tensile Properties and Micromentioning

confidence: 99%

Importance of Bimodal Structure Topology in the Control of Mechanical Properties of a Stainless Steel

Zhang¹,

Orlov

Vajpai

et al. 2014

Adv Eng Mater

Self Cite

View full text Add to dashboard Cite

Refinement of microstructure from ordinary coarsegrained (CG; grain size d ! 10 mm) down to ultrafine-grained (UFG; grain size d 1 mm), and even further to nano-scale, is a well-proven approach for the strengthening of metallic materials. [1][2][3] However, the downside of bulk UFG metals is their rather poor ductility resulting from very limited capacity for dislocation storage and therefore early strain localization during mechanical loading. [2][3][4][5] Since both strength and ductility are important characteristics for the majority of structural applications, various strategies have been suggested to improve the ductility of bulk UFG and nano-structured metals and alloys. [5,6] Among these strategies, fabricating structures with rather wide, gradient or, better, bimodal grain size distributions appear to be very efficient for the enhancement of ductility at a little compromise in strength. [7,8] In such structures, the ultrafine-and nano-scale grains provide the high strength, while the coarser grains store dislocations, therefore, enhancing the ductility characteristics. [3][4][5] Recently, a substantial number of processing routes allowing the fabrication of metallic materials with bimodal grain size distributions have been developed. [8][9][10][11] These routes are based on severe plastic deformation (SPD) [10] and other thermo-mechanical processing techniques [8,9] as well as on powder metallurgy approach. The latter involves mechanical milling (MM) of metal powders, mixing of the MMed and the initial powders (IP), and finally consolidating the mixture. [11] Such processing routes, although effective in the control of UFG/CG fraction ratios, provide very limited control over the spatial topological distribution of the coarse and the fine grains. Therefore, these limited-control microstructures deliver only a limited control over properties.In order to improve the control over the microstructural characteristics, and thus properties, Ameyama and co-workers [12][13][14] recently proposed a novel approach based on the powder metallurgy route. Its peculiar features are: (i) the MM processing is optimized to induce heterogeneous structure in powder particles having CG and nano/UFG structures in their core and periphery, respectively; and (ii) the consolidation is optimized to preserve the heterogeneity. Bulk materials fabricated in this way have bimodal structure with a specific regular spatial distribution of nano/UFG and CG regions. Namely, CG structure is enclosed in a three-dimensional continuously connected network of nano/UFG structure. Therefore, we call them "harmonic structured" materials. Further details about the fabrication route, the "harmonic structure" (HS) design concept, and the benefits of them can be found elsewhere. [12][13][14] Although both the ordinary limited-control bimodal structures and the HSs exhibit a very appealing combination of strength and ductility, the variation of the mechanical properties can be quite large. [6] It is envisaged that the large variation of the mechanical ...

show abstract

Section: Quantitative Characteristics Of Tensile Properties and Micromentioning

confidence: 99%

Importance of Bimodal Structure Topology in the Control of Mechanical Properties of a Stainless Steel

Zhang¹,

Orlov

Vajpai

et al. 2014

Adv Eng Mater

Self Cite

View full text Add to dashboard Cite

show abstract

“…Bimodal structure can be considered as an "artificial composite" composed of two phases possessing identical modulus of elasticity and different strengths. These features make bimodal materials have excellent comprehensive mechanical properties [27].…”

Section: Microstructural Featuresmentioning

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

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

“…These goals can be achieved through developing high strength small sized components. Particularly, Ameyama and co-workers proposed an exquisite microstructural design, called "harmonic structure", which led to significantly better combination of strength and ductility for a variety of metals and alloys, as compared to their homogeneous fine or coarsegrained counterparts [17][18][19][20][21][22]. However, the inferior ductility of UFG Ti64 alloys, as compared to their CG counterparts, required to make further efforts to develop Ti64 alloys with high strength together with high ductility to fulfill the need for stronger and tougher Ti64 alloy for improved performance in service.…”

Section: Introductionmentioning

confidence: 99%

“…The grain refinement is an efficient method of strengthening and creation of ultra-fine grained (UFG) structure in Ti64 alloys led to significant improvements in yield and fracture strengths as compared to their coarse-grained (CG) counterparts [4][5][6][7][8][9][10][11][12]. The harmonic structure is essentially a bimodal microstructure wherein the coarse-grained areas ("core") are present as embedded islands in the matrix of threedimensional continuously connected network ("shell") of finegrained areas [17][18][19][20][21][22]. It has been observed in recent decades that metals and alloys with bimodal grain size distribution exhibited a combination of reasonable ductility and high strength [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Harmonic Structure: An Effective Tailored Heterogeneous Microstructural Design to Strengthen Ti‐6Al‐4V Alloy

Vajpai

Ota

Ameyama

et al. 2016

Proceedings of the 13th World Conference on Titanium

Self Cite

View full text Add to dashboard Cite

The present work focused on the strengthening of Ti-6Al-4V alloy, which is used for a wide range of aerospace and biomedical structural applications. A new tailored heterogeneous microstructural design with bimodal grain size distribution and specific topological distribution of fine and coarse grains, called "harmonic structure", and suitable powder metallurgy (PM) based processing approach has been developed to achieve the same. In the present work, harmonic structured Ti-6Al-4V alloy was successfully prepared via a PM approach consisting of controlled severe plastic deformation of the pre-alloyed powders followed by spark plasma sintering. The microstructural evolution at each stage of processing and mechanical properties of the resulting material was investigated. The harmonic structured Ti-6Al-4V alloy exhibited superior tensile properties as compared to their coarse/fine-grained counterparts. An attempt has been made to understand the correlation between the unique microstructural design and improved mechanical properties in the harmonic structured Ti-6Al-4V alloys.

show abstract

Obtaining Copper with Harmonic Structure for the Optimal Balance of Structure-Performance Relationship

Cited by 72 publications

References 16 publications

Importance of Bimodal Structure Topology in the Control of Mechanical Properties of a Stainless Steel

Importance of Bimodal Structure Topology in the Control of Mechanical Properties of a Stainless Steel

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

Harmonic Structure: An Effective Tailored Heterogeneous Microstructural Design to Strengthen Ti‐6Al‐4V Alloy

Contact Info

Product

Resources

About