Philosophical Magazine A最新文献_第9页

Indentation depth recovery in poly(methyl methacrylate) sheet on the microlength scale 聚甲基丙烯酸甲酯薄板在微长度尺度上的压痕深度恢复

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235722

M. Adams, D. Gorman, S. Johnson, B. Briscoe

引用次数: 11

Contact resistance and phase transformations during nanoindentation of silicon 硅纳米压痕过程中的接触电阻和相变

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235704

A. Mann, D. Heerden, J. Pethica, P. Bowes, T. Weihs

{"title":"Contact resistance and phase transformations during nanoindentation of silicon","authors":"A. Mann, D. Heerden, J. Pethica, P. Bowes, T. Weihs","doi":"10.1080/01418610208235704","DOIUrl":"https://doi.org/10.1080/01418610208235704","url":null,"abstract":"Abstract An electrically conductive VC tip has been used in conjunction with ex-situ transmission electron microscopy (TEM) and micro-Raman spectroscopy to examine the behaviour of silicon during nanoindentation testing. During loading, the contact resistance is low because of the presence of the metallic β-Sn phase of silicon. During unloading, the semimetallic BC8 phase and the rhombohedral R8 phase are formed, giving rise to an increase in the contact resistance. In large indentations there is a pronounced discontinuity in both the contact resistance-depth and load-depth curves during unloading. This signifies the formation of a phase with lower electrical resistance. TEM analysis suggests that this phase is amorphous silicon formed in the centre of large indentations. The position of the discontinuity on the load-depth curve is found to depend on the unloading rate, as would be expected for the generation of an amorphous phase. Micro-Raman analysis is largely in agreement with the TEM results, but the amorphous silicon is seen most clearly when there are cracks present, suggesting that the amorphous phase may be subsurface or generated during the rapid propagation of cracks.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131971522","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: 56

Characteristics of diffusion in Al-Mg alloys with ultrafine grain sizes Al-Mg超细合金的扩散特性

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235736

T. Fujita, Z. Horita, T. Langdon

引用次数: 64

Stress fields near interfaces of aluminium-based metal-matrix composites 铝基金属基复合材料界面附近应力场

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235738

H. Heinrich, A. Vananti, G. Kostorz

引用次数: 3

Nanoindentation of natural diamond 天然金刚石的纳米压痕

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235696

Takeshi Sawa, Kohichi Tanaka

{"title":"Nanoindentation of natural diamond","authors":"Takeshi Sawa, Kohichi Tanaka","doi":"10.1080/01418610208235696","DOIUrl":"https://doi.org/10.1080/01418610208235696","url":null,"abstract":"Abstract This study demonstrates that the plane-strain Young's moduli E* = E/(1 - v 2) of natural diamonds with a weight of less than 0.2 carat can be determined by the technique of nanoindentation, where E is Young's modulus and v is Poisson's ratio. The indentation test with a Berkovich indenter was conducted at loads of 50, 100 and 300 mN for three samples; two were ⟨100⟩ oriented and one was ⟨110⟩ oriented. The indentation curves showed almost an elastic behaviour at 50 mN. We evaluated the E* values by analysing the elastic indentation curves with the removal of the contribution of machine compliances due to the machine frame and the deformation of the mount, which was determined from the data obtained during the unloading of the indentation at loads of 100 and 300 mN. The E* values obtained were 1090 and 1217 GPa for ⟨100⟩- and ⟨110⟩-oriented diamonds respectively. These agree reasonably well with the literature values, 1064 and 1169 GPa respectively, measured by an ultrasonic technique. The value for ⟨100⟩-oriented diamond, E* = 1090 GPa, is recommended to use as the value for the diamond indenter, since the indenter is ordinarily manufactured from a natural diamond with its axis along the ⟨100⟩ direction.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126457292","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: 13

Influence of oxygen on the α → γ massive transformation in a Ti-48 at.% Al alloy 氧对Ti-48 at中α→γ块状相变的影响%铝合金

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235743

W. Lefebvre, A. Loiseau, M. Thomas, A. Menand

{"title":"Influence of oxygen on the α → γ massive transformation in a Ti-48 at.% Al alloy","authors":"W. Lefebvre, A. Loiseau, M. Thomas, A. Menand","doi":"10.1080/01418610208235743","DOIUrl":"https://doi.org/10.1080/01418610208235743","url":null,"abstract":"Abstract The structure and composition of a Ti-48 at.% Al alloy with various oxygen contents, quenched from a homogeneous ci state, have been studied by coupling a one-dimensional atom probe and transmission electron microscopy. When the global oxygen content is lower than 1 at.%, the alloys display massive ym-phase regions and regions having a two-phase (α2 + γ) ultrafine lamellar structure. γm regions are not of a single-phase nature but contain very thin α2 plates. Analyses show that the precipitation of this phase is driven by the excess oxygen in the γm phase. Detailed structural analysis of the ultrafine lamellar structure reveals that it is not formed from either the α phase or the γm phase at high temperatures but at low temperatures from chemically ordered α2 regions. When the oxygen content is higher than 1 at.%, only an ultrafine lamellar structure is observed, meaning that the α → γm massive transformation is suppressed and replaced by the α → α2 → α2 + γ transformations paths. Oxygen is therefore found to favour α2 ordering, the driving force being the extreme difference of solubility of oxygen between α2 and γ.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"256 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122504564","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

The influence of grain size on the indentation hardness of high-purity copper and aluminium 晶粒尺寸对高纯铜、铝压痕硬度的影响

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235717

Y. Y. Lim, M. M. Chaudhri

{"title":"The influence of grain size on the indentation hardness of high-purity copper and aluminium","authors":"Y. Y. Lim, M. M. Chaudhri","doi":"10.1080/01418610208235717","DOIUrl":"https://doi.org/10.1080/01418610208235717","url":null,"abstract":"Abstract Quasistatic microindentation hardness studies of specimens of high-purity polycrystals and single crystals of copper and aluminium have been made at room temperature using a Vickers diamond and a tungsten carbide-cobalt sphere of radius 200 μm. The polycrystalline specimens of copper were prepared by heavy deformation of as-received specimens followed by thermal annealing at different temperatures and for different times; the grain sizes produced were in the range 15-520 μm. The polycrystalline samples of the as-received aluminium had a grain size of 330 ± 40 μm. As-formed specimens of copper of different grain sizes were found to have different dislocation densities; the smaller the grain size, the higher was the dislocation density. The Vickers hardness for a given indenter load, determined using the projected contact areas of indentations, was found to increase with decreasing grain size. Similarly, the Meyer hardness increased with decreasing grain size. It is argued that the observed increase in hardness of the polycrystals with decreasing grain size is due to the initial dislocation densities in the grains and not due to the grain boundaries which, because of the lack of impurities at them, do not appear to act as dislocation barriers in these high-purity fcc metals. Moreover, as the indentation hardness values of single crystals of copper of different orientations are very similar, any differences in the orientations of contiguous grains will not affect the hardness values of polycrystals. Thus for large single crystals of copper (10 mm × 10 mm × 10 mm), having the same dislocation density as that of the polycrystalline specimens of copper of grain size 15 ± 7 μm, the indentation hardness values were quite similar. Experimental results from the indentation hardness tests, made using both Vickers and spherical indenters, on polycrystalline aluminium specimens and relatively large single crystals showed that there was insignificant influence of the grain size.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134359177","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: 75

Scaling relationships for indentation measurements 缩进测量的缩放关系

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235693

Yang-Tse Cheng, Zhiyong Li, Che-Min Cheng

引用次数: 158

How hard is fullerene-like CN x ? Some observations from the nanoindentation response of a magnetron-sputtered coating 像富勒烯一样的cnx有多难?磁控溅射涂层纳米压痕响应的一些观察

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235723

I. A. Garcia, E. G. Berasategui, S. Bull, T. Page, J. Neidhardt, L. Hultman, N. Hellgren

{"title":"How hard is fullerene-like CN x ? Some observations from the nanoindentation response of a magnetron-sputtered coating","authors":"I. A. Garcia, E. G. Berasategui, S. Bull, T. Page, J. Neidhardt, L. Hultman, N. Hellgren","doi":"10.1080/01418610208235723","DOIUrl":"https://doi.org/10.1080/01418610208235723","url":null,"abstract":"Abstract Thin fullerene-like CN x coatings deposited on hard substrates (e.g. SiC) show very shallow residual impressions when investigated by nanoindentation at displacements less than the coating thickness. The low work of indentation (i.e. the small area enclosed by the loading and unloading curves) of these materials implies a large amount of recovery of indent depth which is often associated with materials of high hardness. However, analysis of the unloading curves by the Oliver-Pharr method generates hardness values which are usually less than that of silicon. Detailed analysis of the loading curve shows three distinct regimes of behaviour corresponding to behaviour controlled by surface roughness, elastic deformation and plasticity. Measurements of Young's modulus from the elastic part of the loading curve, from the Oliver-Pharr method and from elastic wave measurements are all consistently low. This implies that the material behaves like a very hard rubber which undergoes considerable elastic recovery on unloading but does not have a very high resistance to penetration on loading. The very high H/E values for fullerene-like CN x confirms this view.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"2017 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121779775","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: 32

Deformation under nanoindents in sapphire, spinel and magnesia examined using transmission electron microscopy 用透射电子显微镜观察蓝宝石、尖晶石和镁砂纳米压痕下的变形

Philosophical Magazine A Pub Date : 2002-07-01 DOI: 10.1080/01418610208235708

S. J. Lloyd, J. Molina-Aldareguia, W. Clegg

引用次数: 42