Philosophical Magazine A最新文献_第6页

Nucleation and growth of deformation twins: A perspective based on the double-cross-slip mechanism of deformation twinning 变形孪晶的形核与长大:基于变形孪晶双交叉滑移机制的视角

Philosophical Magazine A Pub Date : 2002-10-01 DOI: 10.1080/01418610208240069

K. Lagerlöf, J. Castaing, P. Pirouz, A. Heuer

{"title":"Nucleation and growth of deformation twins: A perspective based on the double-cross-slip mechanism of deformation twinning","authors":"K. Lagerlöf, J. Castaing, P. Pirouz, A. Heuer","doi":"10.1080/01418610208240069","DOIUrl":"https://doi.org/10.1080/01418610208240069","url":null,"abstract":"Abstract The nucleation and growth of deformation twins are discussed, assuming that twinning occurs via the double-cross-slip mechanism first postulated by Pirouz for twinning in silicon. The dislocation energetics in this model are described in detail. In all cases, dislocation dissociation occurs and gives rise to a stationary partial and a twinning partial; twin growth involves the twinning partial undergoing double cross-slip. We discuss three specific geometries: firstly, the dissociation of a perfect dislocation into three collinear partials of equal Burgers vectors, which describes basal twinning in sapphire and twinning in bcc metals; secondly, the dissociation of a perfect dislocation into two collinear partials with different Burgers vectors, which describes rhombohedral twinning in sapphire; thirdly, the dissociation of a perfect dislocation into two non-collinear Shockley partials, which is used to describe twinning in silicon. Finally, the double-cross-slip mechanism readily explains the formation of emissary dislocations at the twin-matrix interface of deformation twins in bcc metals.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"23 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":"124720872","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: 111

Correlation of microstructure and mechanical properties with ultrasonic velocity in the Ni-based superalloy Inconel 625 镍基高温合金Inconel 625显微组织和力学性能与超声速度的关系

Philosophical Magazine A Pub Date : 2002-09-01 DOI: 10.1080/01418610208240051

Anish Kumar, V. Shankar, T. Jayakumar, K. Bhanu Sankara Rao, B. Raj

{"title":"Correlation of microstructure and mechanical properties with ultrasonic velocity in the Ni-based superalloy Inconel 625","authors":"Anish Kumar, V. Shankar, T. Jayakumar, K. Bhanu Sankara Rao, B. Raj","doi":"10.1080/01418610208240051","DOIUrl":"https://doi.org/10.1080/01418610208240051","url":null,"abstract":"Abstract Inconel 625 tubes are used extensively in ammonia cracker units of heavy-water plants. During service, the alloy is exposed to temperature close to 873 K for a prolonged period (about 60 000 h), leading to substantial decrease in ductility and toughness of the alloy due to heavy intragranular and intergranular precipitation. Service-exposed Inconel 625 material (873 K for about 60 000 h) was given post-service ageing treatments at different temperatures (923, 1023 and 1123K) up to 500 h. These heat treatments altered the microstructure, which in turn had an influence upon both the tensile properties and the ultrasonic velocity. The alloy that had seen service was solution annealed at 1423 K for 0.5 h followed by ageing at different temperatures (923 and 1123 K) and the influence of these heat treatments on changes in microstructures and in turn their effect on room-temperature tensile properties and ultrasonic velocity have been studied. The present study aims at establishing the correlation between room-temperature tensile properties and ultrasonic velocity with the microstructural changes that occurred during ageing treatments in Ni-based superalloy Inconel 625. For the first time, the present authors have demonstrated the influence of various precipitates, such as intermetallic phases γ″, Ni2(Cr, Mo) and δ, and grain-boundary carbides, on the correlation of yield strength and ultrasonic velocity.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"175 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124212732","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: 36

Modelling grain-boundary resistance in intergranular dislocation slip transmission 模拟晶间位错滑移传递过程中的晶界阻力

Philosophical Magazine A Pub Date : 2002-09-01 DOI: 10.1080/01418610208240050

M. Koning, R. Miller, V. Bulatov, F. F. Abraham

{"title":"Modelling grain-boundary resistance in intergranular dislocation slip transmission","authors":"M. Koning, R. Miller, V. Bulatov, F. F. Abraham","doi":"10.1080/01418610208240050","DOIUrl":"https://doi.org/10.1080/01418610208240050","url":null,"abstract":"Abstract We investigate the resistance on the glide of lattice dislocations between adjacent crystal grains due to the presence of a grain boundary (GB). Applying a combination of molecular dynamics (MD) simulations and a line tension (LT) model we identify the geometrical parameters that are relevant in the description of this process. In the MD simulations we observe slip transmission of dislocation loops nucleated from a crack tip near a series of pure tilt GBs in Ni. The results are rationalized in terms of a LT model for the activation of a Frank-Read source in the presence of a GB. It is found that the slip transmission resistance is a function of only three variables: firstly, the ratio of resolved stress on the incoming slip system to that on the outgoing slip system, secondly, the magnitude of any residual Burgers vector content left in the GB and, thirdly, the angle between the traces of the incoming and outgoing slip planes in the GB plane. Comparison with the MD simulations and experimental data shows that the LT model captures the essential energetics of slip transmission and suggests relatively simple functional relationships between the GB geometry and loading conditions on the one hand and slip transmission resistance on the other.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116577817","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: 127

Nanometre-scale defects in shear bands in a metallic glass 金属玻璃剪切带中的纳米级缺陷

Philosophical Magazine A Pub Date : 2002-09-01 DOI: 10.1080/01418610208240056

Jing Li, F. Spaepen, T. Hufnagel

引用次数: 196

Assessing the mechanical strength of interfacial atomic bonds by quantitative high-resolution transmission electron microscopy 用定量高分辨率透射电子显微镜评估界面原子键的机械强度

Philosophical Magazine A Pub Date : 2002-09-01 DOI: 10.1080/01418610208240060

F. Ernst

{"title":"Assessing the mechanical strength of interfacial atomic bonds by quantitative high-resolution transmission electron microscopy","authors":"F. Ernst","doi":"10.1080/01418610208240060","DOIUrl":"https://doi.org/10.1080/01418610208240060","url":null,"abstract":"Abstract A method is presented for quantitatively assessing the strength of interatomic bonding forces across interfaces between two dissimilar crystalline materials. At such interfaces, the mismatch of corresponding lattice parameters gives rise to a periodic pattern of linear regions of poor match, denoted as ‘misfit dislocations’. The atom displacements that occur in these regions constitute an ‘image’ of the bonding forces across the interface. By fitting a model of the displacement field to experimentally determined atom positions at misfit dislocation cores, therefore, it should be possible to assess the mechanical strength of the interatomic bonds across the interface. The feasibility of this approach is demonstrated for the cube-on-cube interface between a SrTiO3(001) substrate and an epitaxial layer of SrZrO3. The atom positions at the misfit dislocations in this interface were determined with small error limits (0.03 nm) by quantitative high-resolution transmission electron microscopy. By fitting a continuum model describing the displacement field of misfit dislocations as a function of elasticity parameters of the interfacial bond layer and the two juxtaposed crystals, it is possible to determine the shear stiffness of the interatomic bonds across this interface quantitatively and with well-defined error limits (30%). Moreover, the analysis enables determining Poisson's ratio and the shear modulus of epitaxial layers, in this case SrZrO3. The method introduced here has a broad range of applications.","PeriodicalId":114492,"journal":{"name":"Philosophical Magazine A","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129017675","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: 3

Mechanical properties of composites with an icosahedral fibre packing reinforcement 二十面体纤维填料增强复合材料的力学性能

Philosophical Magazine A Pub Date : 2002-09-01 DOI: 10.1080/01418610208240057

R. Dendievel, J. Blandin, Marc Fivel, M. Audier, M. Duneau

引用次数: 9

Quantitative characterization of second-phase particles by atomic force microscopy and scanning electron microscopy 用原子力显微镜和扫描电镜对二相粒子进行定量表征

Philosophical Magazine A Pub Date : 2002-09-01 DOI: 10.1080/01418610208240053

B. Fruhstorfer, V. Mohles, R. Reichelt, E. Nembach

引用次数: 7

Non-isothermal precipitate growth and the principle of additivity 非等温析出物生长与可加性原理

Philosophical Magazine A Pub Date : 2002-09-01 DOI: 10.1080/01418610208240061

M. W. Nordbakke, N. Ryum, O. Hunderi