Philosophical Magazine A最新文献_第5页

An investigation on the transformation of the icosahedral phase in the Al-Fe-Cu system during mechanical milling and subsequent annealing 机械铣削和退火过程中Al-Fe-Cu体系中二十面体相转变的研究

Philosophical Magazine A Pub Date : 2002-11-01 DOI: 10.1080/01418610208239629

N. Mukhopadhyay, T. Yadav, O. Srivastava

{"title":"An investigation on the transformation of the icosahedral phase in the Al-Fe-Cu system during mechanical milling and subsequent annealing","authors":"N. Mukhopadhyay, T. Yadav, O. Srivastava","doi":"10.1080/01418610208239629","DOIUrl":"https://doi.org/10.1080/01418610208239629","url":null,"abstract":"Abstract Icosahedral quasicrystalline material in the Al-Fe-Cu system was mechanically milled in an attritor ball mill (Szegvari attritor) for 1, 3, 6 and 10 h in dry air, at a speed of 400 rev min−1 and with a ball-to-powder ratio of 20 to 1. Structural transformations and the consequent phase evolutions during mechanical milling and subsequent heat treatments were studied by X-ray diffraction, differential thermal analysis (DTA) and transmission electron microscopy techniques. After milling for 1 h, the evolution of disordered B2 phase (a=0.29 nm) was observed to coexist with the parent icosahedral phase, whereas a microstructure consisting of nanosized B2 particles distributed in an amorphous matrix was observed after further milling (3–10 h). However, no sharp peak corresponding to the phase transformation was identified in DTA, but the microstructure of the powder milled for 10 h after the DTA experiment was found to transform to a mixture of icosahedral and B2 phases, where B2 appears to be the major phase in contrast with that in as-cast material. Isothermal heat treatment of powder mechanically milled at 850°C for 10 and 20 h led to complete transformation to a single B2 phase with a high degree of long-range ordering. The implication of these transformations will be discussed with reference to their relative stabilities among the competing phases during milling and subsequent heat treatment.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116154994","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: 19

Microstructural changes in the cell walls of a closed-cell aluminium foam during creep 闭孔泡沫铝在蠕变过程中细胞壁的微观结构变化

Philosophical Magazine A Pub Date : 2002-11-01 DOI: 10.1080/01418610208239623

P. Zhang, M. Haag, Oliver Kraft, Alexander Wanner, Eduard Arzt, Eduard Arzt

引用次数: 18

Single-dislocation-based strengthening mechanisms in nanoscale metallic multilayers 纳米尺度金属多层材料中单位错强化机制

Philosophical Magazine A Pub Date : 2002-11-01 DOI: 10.1080/01418610208239626

Amit Misra, J. Hirth, Harriet Kung

{"title":"Single-dislocation-based strengthening mechanisms in nanoscale metallic multilayers","authors":"Amit Misra, J. Hirth, Harriet Kung","doi":"10.1080/01418610208239626","DOIUrl":"https://doi.org/10.1080/01418610208239626","url":null,"abstract":"Abstract A breakdown from the dislocation-pile-up-based Hall-Petch model is typically observed in metallic multilayers when the layer thickness (one half of the bilayer period) is of the order of a few tens of nanometres. The multilayer strength, however, continues to increase with decreasing layer thickness to a few nanometres. A model based on the glide of single dislocations is developed to interpret the increasing strength of multilayered metals with decreasing layer thickness when the Hall-Petch model is no longer applicable. The model is built on the hypothesis that plastic flow is initially confined to one layer and occurs by the motion of single ‘hairpin’ dislocation loops that deposit misfit-type dislocations at the interface and transfer load to the other, elastically deforming layer. The composite yield occurs when slip is eventually transmitted across the interface, overcoming an additional resistance from the interface dislocation arrays. In a lower-bound estimate, the stress for the initial glide of ‘hairpin’ dislocation loops, confined to one layer, is similar to the classical Orowan stress. In the upper-bound estimate, the interaction of the glide loop with the existing misfit dislocation arrays at the interface is also considered in deriving the Orowan stress. The effect of in-plane residual stresses in the layers on the Orowan stress calculation is also considered. The model predictions compare favourably with experimentally measured strengths on Cu-based multilayers. When the layer thickness is decreased to a couple of nanometres, the strength reaches a plateau and, in some cases, drops with decreasing layer thickness. The single-dislocation model developed here predicts strengthening with decreasing layer thickness and, therefore, does not explain the deformation behaviour in this regime. In the regime of several nanometres, the deformation behaviour can be explained by dislocation transmission across the interface followed by glide of loops that span several layer thicknesses.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126158092","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: 270

Temperature- and electron-beam-induced crystallization of zirconia thin films deposited from an aqueous medium: A transmission electron microscopy study 温度和电子束诱导氧化锆薄膜结晶从水介质沉积:透射电子显微镜研究

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240068

V. Roddatis, D. Su, F. Jentoft, R. Schlögl

引用次数: 15

Changes in precipitate distribution during the low-stress creep of a hydrided magnesium-zirconium alloy 氢化镁锆合金低应力蠕变过程中析出相分布的变化

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240065

K. McNee, G. W. Greenwood, H. Jones

引用次数: 10

Considerations of the double-cross-slip mechanism for basal and rhombohedral twinning in sapphire (α-Al2O3) 蓝宝石(α-Al2O3)基孪晶和菱形孪晶双交叉滑移机制的思考

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240070

A. He, K. Lagerlöf, J. Castaing, A. Heuer

引用次数: 6

Crystal structure and chemical bonding of the high-pressure phase of MgAl2O4 from first-principles calculations 基于第一性原理计算的MgAl2O4高压相的晶体结构和化学键

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240072

C. Fang, G. With

引用次数: 4

Interaction of a piezoelectric screw dislocation with an insulating crack 压电螺旋位错与绝缘裂纹的相互作用

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240067

Tong-Yi Zhang, Tianhong Wang, M. Zhao

{"title":"Interaction of a piezoelectric screw dislocation with an insulating crack","authors":"Tong-Yi Zhang, Tianhong Wang, M. Zhao","doi":"10.1080/01418610208240067","DOIUrl":"https://doi.org/10.1080/01418610208240067","url":null,"abstract":"Abstract The electrical and mechanical fields induced by a piezoelectric screw dislocation near an electrically insulating elliptical cavity in a piezoelectric material are derived through the image dislocation approach by considering the electric field inside the cavity. When the cavity is reduced to a crack, three outcomes are possible. The three outcomes correspond to three different electrical boundary conditions along the crack faces, depending on the α/β; ratio, where α; is the ratio of the minor semiaxis to the major semiaxis of the ellipse and β; is the ratio of the dielectric constant of the cavity to the effective dielectric constant of the piezoelectric material. The crack is electrically impermeable when α/β; → ∞ the crack becomes electrically permeable as α/β; → 0. Since the minimum of the dielectric constant has a finite non-zero value and a real crack also has a non-zero width, the α/β; ratio will generally have a finite non-zero value, resulting in a semi-impermeable crack. Furthermore, the difference in the electric boundary conditions leads to great differences in the image force acting on the dislocation, in the intensity factors and in the J integral for crack propagation induced by the dislocation.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"198 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132684608","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: 21

Dislocation motion in a random solid solution 随机固溶体中的位错运动

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240071

M. Zaiser

引用次数: 38

Interaction of lattice dislocations with the α-γ interphase interface in a stainless steel bicrystal 不锈钢双晶中晶格位错与α-γ界面的相互作用

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240066

A. Taisne, B. Décamps, L. Priester

引用次数: 2