Unique Mechanical Properties of Nanostructured Metals

2007 ◽  
Vol 7 (11) ◽  
pp. 3765-3770 ◽  
Author(s):  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Equivalent Strain ◽  
Coarse Grained ◽  
Roll Bonding ◽  
Nanostructured Metals ◽  
Ultrafine Grained ◽  
Nanocrystalline Structures ◽  
Rolling Deformation

Recently, it becomes possible to fabricate bulk metals having ultrafine grained or nanocrystalline structures of which grain size is in nano-meter dimensions. One of the promising ways to realize bulk nanostructured metals is severe plastic deformation (SPD) above logarithmic equivalent strain of 4. We have developed an original SPD process, named Accumulative Roll Bonding (ARB) using rolling deformation in principle, and have succeeded in fabricating bulk nanostructured sheets of various kinds of metals and alloys. The ARB process and the nanostructured metals fabricated by the ARB are introduced in this paper. The nanostructured metals sometimes perform quite unique mechanical properties, that is rather surprising compared with conventionally coarse grained materials. The unique properties seem to be attributed to the characteristic structures of the nano-metals full of grain boundaries.

Unique Mechanical Properties of Nanostructured Metals

2007 ◽  
Vol 7 (11) ◽  
pp. 3765-3770 ◽  
Author(s):  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Equivalent Strain ◽  
Coarse Grained ◽  
Roll Bonding ◽  
Nanostructured Metals ◽  
Ultrafine Grained ◽  
Nanocrystalline Structures ◽  
Rolling Deformation

Recently, it becomes possible to fabricate bulk metals having ultrafine grained or nanocrystalline structures of which grain size is in nano-meter dimensions. One of the promising ways to realize bulk nanostructured metals is severe plastic deformation (SPD) above logarithmic equivalent strain of 4. We have developed an original SPD process, named Accumulative Roll Bonding (ARB) using rolling deformation in principle, and have succeeded in fabricating bulk nanostructured sheets of various kinds of metals and alloys. The ARB process and the nanostructured metals fabricated by the ARB are introduced in this paper. The nanostructured metals sometimes perform quite unique mechanical properties, that is rather surprising compared with conventionally coarse grained materials. The unique properties seem to be attributed to the characteristic structures of the nano-metals full of grain boundaries.

Investigations on Microstructure Evolution and Deformation Behavior of Aged and Ultrafine Grained Al-Zn-Mg Alloy Subjected to Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 253-258
Author(s):  
Wei Ping Hu ◽  
Si Yuan Zhang ◽  
Xiao Yu He ◽  
Zhen Yang Liu ◽  
Rolf Berghammer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Microstructure Evolution ◽  
Deformation Behavior ◽  
Deformation Mechanisms ◽  
Mg Alloy ◽  
Ultrafine Grained

An aged Al-5Zn-1.6Mg alloy with fine η' precipitates was grain refined to ~100 nm grain size by severe plastic deformation (SPD). Microstructure evolution during SPD and mechanical behaviour after SPD of the alloy were characterized by electron microscopy and tensile, compression as well as nanoindentation tests. The influence of η' precipitates on microstructure and mechanical properties of ultrafine grained Al-Zn-Mg alloy is discussed with respect to their effect on dislocation configurations and deformation mechanisms during processing of the alloy.

Influence of Severe Plastic Deformation on Mechanical Properties of an AA5024 Alloy

2016 ◽  
Vol 879 ◽  
pp. 1317-1322 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Yuzbekova ◽  
Tatiana Lebedkina ◽  
Mikhail Lebyodkin ◽  
Rustam Kaibyshev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Coarse Grained ◽  
Type B ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Elongation To Failure ◽  
Dislocation Strengthening

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.

Texture Evolution of Armco Iron during Accumulative Roll Bonding Process

2011 ◽  
Vol 702-703 ◽  
pp. 177-181
Author(s):  
Erell Bonnot ◽  
François Brisset ◽  
Anne Laure Helbert ◽  
Thierry Baudin
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Accumulative Roll Bonding ◽  
Armco Iron ◽  
Texture Evolution ◽  
Equivalent Strain ◽  
Electron Backscattered Diffraction ◽  
Roll Bonding ◽  
Number Of Cycles

The Armco iron is one of the purest commercial iron with very low levels of carbon, oxygen and nitrogen. In order to improve the mechanical properties, it is worth applying severe plastic deformation to obtain ultrafine-grained bulk materials, with grain size <1µm. In this study, samples of Armco iron were subjected to a technique of severe plastic deformation named Accumulative Roll Bonding (ARB). The important parameter of ARB is the number of cycles and then the von Mises equivalent strain. By means of the Electron BackScattered Diffraction (EBSD) technique, the texture evolution with the number of cycles was studied. The microhardness was also measured in function of the equivalent strain. Finally, the mean grain size and the fraction of high angle grain boundaries were determined as a function of the number of cycles.

Evolution of Microstructure and Texture of Pure Al Single Crystal Having {112} Orientation during Severe Plastic Deformation

2007 ◽  
Vol 26-28 ◽  
pp. 405-408 ◽  
Author(s):  
Naoki Ishida ◽  
Daisuke Terada ◽  
Keizo Kashihara ◽  
Nobuhiro Tsuji
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Single Crystal ◽  
Accumulative Roll Bonding ◽  
Equivalent Strain ◽  
Roll Bonding ◽  
Single Crystal Specimen ◽  
Ultrafine Grained ◽  
The Matrix ◽  
Evolution Of Microstructure

The sheet of pure Al (99.99%) single crystal having (1 12)[110] orientation was deformed up to equivalent strain of 6.4 by the accumulative roll-bonding (ARB) process. The microstructures and orientation of the single crystal ARB-processed by various cycles were characterized by the EBSP measurement. After 1cycle-ARB process, the crystal was macroscopically subdivided into two matrices (macroscopic grain subdivision). These matrices exhibits two different variants of brass orientation, which are (1 01)[121] and (011)[211]. In addition to the macroscopic grain subdivision, microscopic grain subdivision also occurred within the matrix to form an ultrafine grained structure in the single crystal specimen after high strains.

Effect of Working Temperature on Microstructure and Mechanical Properties of Ultrafine Grained Al and Al-5vol.%SiCp Composite Processed by Accumulative Roll-Bonding

2007 ◽  
Vol 534-536 ◽  
pp. 1381-1384
Author(s):  
Seong Hee Lee ◽  
Si Young Chang ◽  
Sung Tag Oh
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Accumulative Roll Bonding ◽  
Equivalent Strain ◽  
Roll Bonding ◽  
Working Temperature ◽  
Microstructure And Mechanical Properties ◽  
Ultrafine Grained ◽  
Coarse Grains ◽  
Almost All

The effect of working temperature on microstructure and mechanical properties of ultrafine grained monolithic Al and Al-5vol.%SiCp composite processed by accumulative roll bonding (ARB) was studied. The ARB was performed up to eight cycles (an equivalent strain of ~6.4) without lubricant. The working temperature was varied from ambient temperature to 200 C. The samples processed at temperatures below 100C exhibited an ultrafine grained structure over almost all regions. However, the samples processed at 200C showed an inhomogeneous structure in which a few coarse grains due to an occurrence of conventional recrystallization is partially seen. The tensile strength of both the monolithic Al and the composite decreased with increasing the ARB working temperature. The variation of microstructure and mechanical properties of the composite with the working temperature was compared to that of the monolithic aluminum.

Production of Nanostructure in Titanium by Cold Rolling

2008 ◽  
Vol 584-586 ◽  
pp. 759-764 ◽  
Author(s):  
Svetlana Malysheva ◽  
G.A. Salishchev ◽  
Sergey Mironov ◽  
Sergey V. Zherebtsov
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Cold Rolling ◽  
Sheet Material ◽  
Coarse Grained ◽  
Sheet Rolling ◽  
Commercial Titanium ◽  
High Level

The paper considers changes in microstructure, texture and mechanical properties of commercial titanium with initial coarse-grained structure during cold sheet rolling. It has been shown that rolling above 75% leads to formation of a uniform nanocrystalline (NC) structure with a grain size of approximately 0.2 'm in the sheet material. The sheets have a high level of mechanical properties which is comparable with the properties of bulk specimens of titanium with NC structure produced by some other method of severe plastic deformation.

Mechanical Behaviors of Ultrafine Grained Metallic Materials

2007 ◽  
Vol 124-126 ◽  
pp. 1325-1328
Author(s):  
Dong Hyuk Shin ◽  
Duck Young Hwang ◽  
Jung Yong Ahn ◽  
Kyung Tae Park ◽  
Yong Suk Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Coarse Grained ◽  
Metallic Materials ◽  
Room Temperature Ductility ◽  
Ultrafine Grained ◽  
Superior Mechanical Properties ◽  
Ultrafine Grained Materials ◽  
The Relationship

Ultrafine grained materials fabricated by severe plastic deformation exhibit both superior and inferior mechanical properties, as the prominent structural materials, compared to coarse grained counterparts. The superior mechanical properties are ultrahigh strength and exceptional ductility at high temperatures (i.e., superplasticity). The inferior mechanical properties are lack of strain hardenability and room temperature ductility. In this study, the relationship between microstructure and mechanical properties of ultrafine grained materials fabricated by severe plastic deformation is investigated in order to provide insight broadening their future applicability.

Difference in Annealing Characteristics of Nanostructured Copper Alloys Processed by Accumulative Roll Bonding

2007 ◽  
Vol 124-126 ◽  
pp. 1373-1376
Author(s):  
Seong Hee Lee ◽  
Seung Zeon Han ◽  
Cha Yong Lim
Keyword(s):  
Mechanical Properties ◽  
Accumulative Roll Bonding ◽  
Copper Alloys ◽  
Coarse Grained ◽  
Roll Bonding ◽  
Annealing Temperatures ◽  
Microstructure And Mechanical Properties ◽  
Ultrafine Grained ◽  
The Difference ◽  
Nanostructured Copper

The difference in annealing characteristics of oxygen free copper (OFC) and deoxidized low-phosphorous copper (DLP) processed by ARB was studied. The copper alloys processed by eight cycles of the ARB were annealed for 10 minutes at various temperatures ranging from 100 to 400°C. The variation of microstructure and mechanical properties with annealing was significantly different in both copper alloys. In case of OFC, the ultrafine grained (UFG) structure formed by the ARB still remained up to 200°C, and above 200°C it was completely replaced with a coarse grained structure due to an occurrence of the conventional recrystallization. However, in case of DLP, the recrystallization did not occur even at 350°C. The strength of the OFC also decreased significantly at annealing temperatures above 200°C, while the hardness of the DLP did not decrease so largely up to 350°C. These differences in annealing characteristics in both copper alloys were discussed in terms of purity.

Microstructural and Textural Evolutions of OFHC Cu during the CECC Process and Annealing Treatment

2020 ◽  
Vol 993 ◽  
pp. 434-444
Author(s):  
Yang Wu ◽  
Da Yu Shu ◽  
Jun Cen Qu ◽  
Gao Zhan Zhao ◽  
Mao Chuan Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Efficiency ◽  
Effective Strain ◽  
Annealing Treatment ◽  
Coarse Grained ◽  
High Ductility ◽  
Ultrafine Grained ◽  
Different Temperatures ◽  
Ultrafine Grained Microstructure

The bulk Cu billets with ultrafine-grained microstructure were successfully processed from full-annealed coarse grained oxygen-free high conductivity (OFHC) Cu by the cyclic extrusion and closed compression (CECC), subsequently annealed at different temperatures. The evolution of the microstructure and mechanical properties was systematically studied. The results show that the effective strain per CECC process is ε=2.77, with further annealing treatment, a high-efficiency grain refinement is realized. After two cycles of CECC process and annealing at 350 °C for 1 h, the grain size refined to ～3 μm, the tensile strength increased to 280 MPa with a high ductility of 54%. Furthermore, a homogeneous structure and mechanical properties in the bulk copper billets for post-forging could be obtained.

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