Nanostructured Materials最新文献_第9页

Fatigue properties of 5056 Al-Mg alloy produced by equal-channel angular pressing 等径角挤压5056 Al-Mg合金的疲劳性能

Nanostructured Materials Pub Date : 1999-10-01 DOI: 10.1016/S0965-9773(99)00392-X

A Vinogradov , S Nagasaki , V Patlan , K Kitagawa , M Kawazoe

{"title":"Fatigue properties of 5056 Al-Mg alloy produced by equal-channel angular pressing","authors":"A Vinogradov , S Nagasaki , V Patlan , K Kitagawa , M Kawazoe","doi":"10.1016/S0965-9773(99)00392-X","DOIUrl":"10.1016/S0965-9773(99)00392-X","url":null,"abstract":"<div>The fatigue behaviour of the fine-grain 5056 Al-alloy processed by equal-channel angular pressing (ECAP) is explored. This material exhibits a slightly enhanced fatigue life at low stress amplitudes. However, no improvement in the fatigue limit is observed. Fatigue performance is discussed in terms of fatigue life, crack nucleation and propagation. Structural changes during fatigue are investigated by transmission electron microscopy. It is shown that the fine structure achieved during processing is unstable and tends to relax with cycling, resulting in local recovery of the pre-deformed material. Structure relaxation during fatigue is supposed to provoke notable cyclic softening which is particularly pronounced at higher applied stresses. It is found that the crack growth rate is greater in the fine-grain ECAP material than in its coarse-grain counterpart. The latter is attributed to the roughness-induced crack closure and crack deflections which is more significant in conventional alloy. The improvement of fatigue properties at low-cyclic regime is believed to be due to a higher resistance to crack nucleation in the fine-grained material having a larger yield stress value.</div>","PeriodicalId":18878,"journal":{"name":"Nanostructured Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0965-9773(99)00392-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82841960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 139

The effect of heat treatment on tensile properties of the cold-compacted nanocrystalline Al 热处理对冷压纳米晶Al拉伸性能的影响

Nanostructured Materials Pub Date : 1999-10-01 DOI: 10.1016/S0965-9773(99)00391-8

X.K. Sun , H.T. Cong , M. Sun , M.C. Yang

{"title":"The effect of heat treatment on tensile properties of the cold-compacted nanocrystalline Al","authors":"X.K. Sun , H.T. Cong , M. Sun , M.C. Yang","doi":"10.1016/S0965-9773(99)00391-8","DOIUrl":"10.1016/S0965-9773(99)00391-8","url":null,"abstract":"<div>The present work studied the effect of heat treatment on tensile properties of bulk nanocrystalline Al (nano-Al) cold-compacted from nano-Al powder. The nano-Al powder synthesized by the active H plasma evaporation was compacted under 1.42 GPa pressure at room temperature into disks with 25 mm diameter and 2 mm thickness. The cold-compacted disks were heat-treated at temperature range from 540°C to 635°C, then machined into the tensile specimens with 25 mm total length. The results indicated that the grain size of the cold-compacted nano-Al heat-treated at 635°C is basically consistent with the primary powder. The tensile specimens heat-treated at temperatures lower than 600°C are broken prematurely in the elastic deformation region during the tensile test process with a brittle intergranular fracture. The specimens heat-treated at temperatures higher than 600°C give the complete stress-strain curves, the yield strengths σ0.2 and tensile strengths σb are 12–16 times and 5–6 times those of annealed coarse-grained Al respectively, the elongations-to-failure are all 4%, and the mechanism of failure is transgranular shear fracture with a ductile dimples fracture.</div>","PeriodicalId":18878,"journal":{"name":"Nanostructured Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0965-9773(99)00391-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78690229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Infrared spectral studies of ammonium polyacrylate adsorbed on nano-zirconia powder surfaces 纳米氧化锆粉体表面吸附聚丙烯酸铵的红外光谱研究

Nanostructured Materials Pub Date : 1999-10-01 DOI: 10.1016/S0965-9773(99)00381-5

Fengqiu Tang , Xiaoxian Huang , Lianzhou Wang , Jingkun Guo

引用次数: 9

Driving mechanisms on mechanical alloying: experimental and molecular dynamics discussions 机械合金化的驱动机制:实验和分子动力学讨论

Nanostructured Materials Pub Date : 1999-10-01 DOI: 10.1016/S0965-9773(99)00397-9

I.F Vasconcelos , R.S de Figueiredo

引用次数: 8

Sintering of bimodal alumina powder mixtures with a nanocrystalline component 具有纳米晶成分的双峰氧化铝粉末混合物的烧结

Nanostructured Materials Pub Date : 1999-10-01 DOI: 10.1016/S0965-9773(99)00380-3

B.G Ravi , R Chaim , A Gedanken

引用次数: 17

Small angle scattering of synchrotron radiation on nanosized CeO2 and CeO2-SnO2 thin films obtained by sol-gel dip-coating method 溶胶-凝胶浸渍法制备的纳米CeO2和CeO2- sno2薄膜上同步辐射的小角散射

Nanostructured Materials Pub Date : 1999-10-01 DOI: 10.1016/S0965-9773(99)00390-6

A Turković , P Dubc̆ek , Z Crnjak-Orel , S Bernstorff

引用次数: 10

Metastability in Fe62.5Co6Ni7.5Zr6Nb2Cu1B15 amorphous alloy and optimisation of its magnetoelastic response Fe62.5Co6Ni7.5Zr6Nb2Cu1B15非晶合金的亚稳态及其磁弹性响应优化

Nanostructured Materials Pub Date : 1999-09-01 DOI: 10.1016/S0965-9773(99)00370-0

L Lanotte , G Ausanio , V Iannotti , F Branda , G Luciani , A Stantero , F Vinai , M Carbucicchio

引用次数: 7

The volume fraction evolution in nanocrystallizing Al-Y-Ni-Fe alloy studied by means of electrical resistivity 用电阻率法研究了纳米晶Al-Y-Ni-Fe合金的体积分数演化

Nanostructured Materials Pub Date : 1999-09-01 DOI: 10.1016/S0965-9773(99)00361-X

P. Jaśkiewicz , K. Pȩkała , J. Latuch

引用次数: 2

Structural and magnetic study of mechanically alloyed Fe-Ni 机械合金化铁-镍的结构和磁性研究

Nanostructured Materials Pub Date : 1999-09-01 DOI: 10.1016/S0965-9773(99)00368-2

M Pȩkała , D Oleszak , E Jartych , J.K Żurawicz

{"title":"Structural and magnetic study of mechanically alloyed Fe-Ni","authors":"M Pȩkała , D Oleszak , E Jartych , J.K Żurawicz","doi":"10.1016/S0965-9773(99)00368-2","DOIUrl":"10.1016/S0965-9773(99)00368-2","url":null,"abstract":"<div>The FexNi100-x (x = 50, 65 and 80) alloys were synthesized in a conventional horizontal low energy ball mill. The X-ray diffraction was used to identify and characterise various phases during the milling process of the Fe80Ni20 alloy exhibiting a bcc structure whereas for x = 65 and 50 the fcc structures are found. The steady state grain size is about 10 nm. Magnetisation measurements after various milling periods allow to monitor a rate at which Ni atoms dissolve in the iron lattice. The room temperature values of the effective magnetic moment raise with the increasing milling period. All the alloys studied exhibit the ferromagnetic ordering. The magnitude of the magnetic interactions is moderately suppressed at prolonged milling as revealed by the Curie temperatures reduced down to 950 K. Such variations are caused by the deviations in the interatomic arrangements of atoms especially in the intergrain regions. The Moessbauer spectroscopy confirmed the ferromagnetic ordering and was used to calculate the distribution of hyperfine magnetic fields. The mean hyperfine fields are 33.8 T for Fe80Ni20 and correspond to the one to two Ni atoms in nearest neighbourhood. In the remaining alloys, at most, five Ni atoms are located in a neighbourhood of the Fe atom.</div>","PeriodicalId":18878,"journal":{"name":"Nanostructured Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0965-9773(99)00368-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82711850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27

Electron holography of ferromagnetic nanowires 铁磁纳米线的电子全息

Nanostructured Materials Pub Date : 1999-09-01 DOI: 10.1016/S0965-9773(99)00358-X

C. Beeli

{"title":"Electron holography of ferromagnetic nanowires","authors":"C. Beeli","doi":"10.1016/S0965-9773(99)00358-X","DOIUrl":"10.1016/S0965-9773(99)00358-X","url":null,"abstract":"<div>Off-axis electron holography has been applied in order to investigate quantitatively the remanent magnetization state of single ferromagnetic Co93Cu7 and Ni nanowires, respectively. The magnetization reversal of an individual Co93Cu7 nanowire has been followed by observing a series of remanent states, obtained ex-situ by applying different external magnetic field sweeps parallel to the nanowire axis. The relation between mis-oriented crystal grains and non-uniform magnetization states has been studied by the combination of electron holography and conventional transmission electron microscopy. Nickel nanowires have been heated in-situ to temperatures above the Curie temperature and cooled down again. The magnetic state during the heating experiment was followed by a series of electron holograms. A single Ni nanowire was examined in detail. It was observed to be uniformly magnetized before the heating cycle. The ferromagnetic state spontaneously formed upon cooling from above the Curie temperature, exhibited a magnetic state with two antiparallel magnetic domains.</div>","PeriodicalId":18878,"journal":{"name":"Nanostructured Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0965-9773(99)00358-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90941813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10