bluuebunny/crossref_metadata_2025 huggingface dataset:
Strasbourg entre la Suède et l’Empire
Authors: des XIII La journée du novembre au Conseil , Krieger Pierre
Published: November 2016

L’étude de la guerre de Trente Ans et du XVIIe siècle en Alsace, et, par extension, à Strasbourg, demeure aujourd’hui un parent pauvre des études historiques concernant notre région. Plusieurs raisons expliquent cet état de fait : les difficultés paléographiques et de compréhension de la langue dans les documents d’archives sont très importantes et, surtout, la part d’historiens germanophones en Alsace devient de plus en plus ténue. En effet, peu de travaux d’envergure ont été menés depuis ceux de Jean-Baptiste Ellerbach, de Rodolphe Reuss et, plus récemment, de Jean-Pierre Kintz dans les domaines social et économique surtout. Ainsi, par cet article, nous allons tenter d’apporter de nouveaux éléments à ces recherches et nous intéresserons à une infime partie de l’histoire de ce « Schwedenkrieg » à Strasbourg, c’est-à-dire à la journée du 16 novembre 1631 au Conseil des XIII dans la ville libre d’Empire de Strasbourg. Cet article est issu de notre mémoire de master intitulé « La ville libre d’Empire de Strasbourg et la Suède de Gustave II Adolphe durant la guerre de Trente Ans : négociations, alliance et propagande (1631-1633) » soutenu en 2014. Nous suivrons pas à pas de houleux débats et des négociations dans la Chambre strasbourgeoise concernant la ligne politique directrice à suivre pour la République, débats qui scelleront l’avenir de la cité rhénane.
Mémoires Frank : l’étonnant destin d’un témoignage historique de deux grands médecins liés à l’Alsace
Authors: Edel Philippe
Published: November 2016

La mémoire des migrants perdure rarement dans leur pays d’origine. C’est le cas du professeur de médecine Jean Pierre Frank, petit-fils d’un fournisseur des armées originaire d’Alsace, qui fit une brillante carrière académique dans de prestigieuses universités d’Allemagne, d’Italie et de Russie et devint célèbre au début du XIXe siècle comme pionnier de l’hygiène publique. Son fils Joseph, également médecin et universitaire, rédigea leurs mémoires qui constituent un remarquable témoignage historique sur les pratiques médicales et sur la vie sociale et culturelle en Europe pendant près d’un siècle. Strasbourg y est cité à plusieurs reprises. Rédigé en français, langue internationale par excellence à l’époque, ce volumineux manuscrit – près de 3 500 pages – n’a paradoxalement jamais été publié dans sa version originale, alors que d’importants chapitres l’ont été au XXe siècle et au début du XXIe siècle en allemand, anglais, italien, polonais, lituanien. Ce document présente pourtant un réel intérêt, notamment pour l’Alsace avec laquelle les Frank ont entretenu des liens singuliers.
Leonhard Baldner – Zu seinem Testament und Nachlassverzeichnis
Authors: Fluck Hans-R. , Scharbach Albert
Published: November 2016

Cette contribution présente deux documents provenant des Archives Municipales de Strasbourg qui ont disparu là-bas depuis longtemps et que l’on retrouve maintenant dans des collections privées. Il s’agit en premier lieu du testament du pêcheur et magistrat strasbourgeois Leonhard Baldner (1612-1694) qui est connu pour ses études de la faune locale du Rhin Supérieur (livre sur les oiseaux, poissons et animaux). En deuxième lieu, elle concerne l’inventaire des biens réalisé après sa mort par l’étude du notaire Johannes Kitsch. Les deux documents mettent en évidence que Leonhard Baldner n’était pas – tel qu’il est peint de façon romancée dans la littérature – un pauvre et simple pêcheur avec un talent particulier pour l’observation de la nature. Il apparait de manière claire qu’il était un membre très apprécié de la corporation des pêcheurs, un bourgeois aisé et érudit ainsi qu’un père de famille attentionné. Il fut en mesure de laisser à son épouse et à ses enfants un patrimoine considérable. De plus ces documents nous apprennent la date, jusqu’à présent inconnue, de son décès : le 1er février 1694.
Emerging Narratives of a Sustainable Urban Neighbourhood: The Case of Vancouver’s Olympic Village
Authors: Westerhoff Lisa M
Published: October 2016

Vancouver’s Olympic Village neighbourhood has been credited with playing an important role in shifting the city towards a more comprehensive approach to sustainability. Like many other urban sustainability efforts at the neighbourhood scale, however, little is known as to the actual performance of the neighbourhood from the perspective of its occupants. To help fill this gap, I present a framework for the evaluation of the performance of sustainable neighbourhoods that that combines insights from narrative and social practice theories to explore how certain narratives of sustainable living are created, translated into practice, and play out in the lives of the principal constituents they affect. In doing so, I begin to reveal the qualitatively felt, experiential dimensions of being in this new form of development, with important lessons for the design, construction and management of future sustainable neighbourhood projects. The study shows that a narrative of liveability and the consideration of short-term quality of life benefits is central to the achievement of ecological and emissions goals. However, an in-depth consideration of the needs of lower income populations is necessary to ensure that the benefits of sustainable living are distributed evenly across socio-economic tiers.
The Influence of the Punch Shape and the Cutting Method on the Limit Strain in the Hole Expansion Test
Authors: Krawczyk Jakub , Gronostajski Zbigniew , Polak Sławomir , Jaśkiewicz Karol , Chorzępa Władysław , Pęcak Ireneusz
Published: November 2016

The article presents a comparison of the hole-flange factors for four steel sheets which have different strength parameters. Three types of punches were applied in the research: cylindrical, spherical and conical. The holes in the samples were made with the use of the following cutting technologies: laser cutting, electrodischarge method using wire and punching. The coefficient of the hole expansion shows that the shape of the used tools has a great impact on the final diameter of the hole. The greatest enlargement of the diameter was obtained for the conical punch, a smaller enlargement for the spherical one and the smallest enlargement for the cylindrical punch. The results of the hole expansion tests using the conical punch diverge from the general rule saying that the greater the plastic deformation of the sheet metal during tensile tests, the more you can enlarge the hole before cracking appears.
Evaluation of Tribological Performance of Lubricants and Nitrided Die for Hot Forming of Steel Using Tapered-Plug Penetration Test
Authors: Asai Kazuhito , Kitamura Kazuhiko
Published: November 2016

High performances of tool materials and lubricants have been necessarily developed to extend die life for hot forming of steel. To promote the developments, economical and simple evaluation testing methods have been required. Tribological performances of tool materials, surface treatments, and lubricants are examined by this test. In this paper, a tapered-plug penetration test has been devised for hot forming of steel. It was found that the combination of an appropriate non-graphite lubricant and a nitride die was effective in reducing in galling and friction between a die and a work by the tapered-plug penetration test.
Influence of Strain Gradient on Springback of Thin Pure Titanium Foils in Microbending Assisted by Resistance Heating
Authors: Zheng Qiu , Shimizu Tetsuhide , Yang Ming
Published: November 2016

Strain gradient is known as an important factor that influences springback of bent components in microscale. Compared with thicker foils, thinner foils usually indicate more strain gradient due to non-uniform material deformation. A resistance heating (RH) method is an effective approach to obtain homogenous material flow by heating foils within only several minutes. To predict springback of foils bent at elevated temperatures, an investigation of the influence of strain gradient on springback is indispensable. To achieve this, microbending tests assisted by RH were conducted at different temperatures ranging from 298 to 723 K in the present study. 0.05 mm-thick pure Ti foils with varying grain sizes of 2.7, 14.7, and 24.5 μm were used. As results, normalized bending moment decreased with increasing temperature and with increasing grain size. The less strain gradient of the foils with larger grain size and at elevated temperatures was confirmed to be the reason according to a theoretical analysis of springback using the constitutive model considering statically stored dislocations (SSDs) and geometrically necessary dislocations (GNDs). The predicted normalized bending moment by theoretical calculation showed good agreement with experimental results at the temperature of 573 K or higher but not at the temperature lower than 573 K. It was found that the springback of the foils was influenced by the strain gradient at low temperatures. Furthermore, the size effects caused by strain gradient reduced as the bending temperature increases.
Effect of Different Quench Media on the Microstructure and Mechanical Properties of Large-Scale Low Alloy Steel Forgings
Authors: Saldana-Garza Edgar Ivan , Wynne Bradley P. , Cerda-Rojas Rene , Mercado-Solis Rafael D.
Published: November 2016

Large-scale forging segments with two different section thicknesses (100 and 250 mm) were separately subjected to water, polymer solution and vegetable oil quenching and then tempered to evaluate the influence of cooling rate on microstructure and mechanical properties under industrial conditions. Regardless of quenching media, the fastest cooling rates are obtained in the thin (100 mm) sections of the ring segments. For the two cross sections, water and vegetable oil generated the faster and slower cooling times, whilst an intermediate cooling timebetween that of water and oil was achieved with polymer solution. Slightly enhanced mechanical properties in the thin sections are associated to the presence of fine mixtures of tempered martensite and tempered bainite (lower type morphology) compared to the thick section microstructure mostly composed of coarse tempered bainite with granular and lower type morphologies and small amounts of tempered martensite. The results obtained in this study also suggest the possibility of using vegetable oil as an alternative quenching media for large-scale forgings with high-specification requirements.
Effect of the Time between Last Deformation Pass and Accelerated Cooling on the Mechanical Properties in Nb and Nb-Mo Microalloyed Steels
Authors: Larzabal Gorka , Isasti Nerea , Rodriguez-Ibabe J.M. , Gutiérrez Isabel , Uranga P.
Published: November 2016

The microstructural refinement induced when the holding time between last deformation pass and accelerated cooling is reduced, affects the mechanical properties in low carbon Nb and Nb-Mo microalloyed steels. Plane strain compression tests were performed and mechanical property samples machined in order to quantify this effect using tensile and Charpy impact tests. A complete microstructural characterization was carried out using electron backscattered diffraction (EBSD) measuring unit size distributions and homogeneity of complex microstructures. The synergetic combination of Nb and Mo elements modifies the final microstructures and, therefore, affects the contribution of different strengthening mechanisms, such as substructure, precipitation hardening and dislocation density. Even though strength is not clearly affected by the reduction of the holding time after the last deformation pass, Charpy properties are considerably improved in the case of the Nb steel. The presence of MA islands in the Nb-Mo steel limits the beneficial effect of the microstructural refinement and toughness remains unmodified.
Enhancing the Strain-Hardening Behavior of Hadfield Steel Using Ladle Treatment Technique
Authors: El-Fawkhry Mohamed K. , Farahat Ahmed Ismail Zaky , Ghali Saeed N.
Published: November 2016

Ladle treatment of molten Hadfield steel considers as the new effective technique for producing Hadfield steel instead of conventional heat treatment process. New eutectic is formed as a result of the ladle treatment process. In this research, the strain-hardening property of the four grades of Hadfield steel containing granular new eutectic phase has been investigated, and compared with the conventional Hadfield steel. Optical and scanning electron microscope reveal that slip bands fractions vary through the five grades of steel as a result of deformation. XRD observation refers to the austenite phase is still the dominant phase through the whole five grades of steel after deformation. The results of the compression and hardness tests clarify that the new granular eutectic phase has a significant effect on the strain-hardening behavior, austenite stability. The nodularity of new eutectic phase is a considerable parameter in the function of yield strength, and hardness increment as well.
Investigation of Uniaxial Tensile Properties of AA6082 under HFQ® Conditions
Authors: Li N. , Shao Zhu Tao , Lin Jian Guo , Dean Trevor A.
Published: November 2016

For a metal forming process, the uniaxial tensile properties of a material are the most fundamental and important properties to investigate. Solution heat treatment, forming and in-die quenching (HFQ®) is a patented process to form complex shape panel components using aluminium alloys at high efficiency and low cost. A Gleeble materials thermo-mechanical simulator was used to conduct uniaxial tensile testing of AA6082 under HFQ® conditions. A set of grips were specially designed to reduce the heat loss of specimen during testing in a Gleeble and allow the strain measurement by using digital image correlation (DIC) system. A large dog-bone specimen with parallel length of 80mm was designed to minimise the temperature gradient along the gauge section. Temperature gradient was measured and uniaxial tensile tests were conducted at the range of deformation temperature of 350-535 °C and the range of strain rate of 0.1-4 /s. The uniaxial tensile properties of AA6082 at different temperatures and strain rates under HFQ® conditions were summarised and the viscoplastic response of the material was discussed.
Microstructural Evolution of the Magnesium Alloy AZ31 with and without SiC Particles during Ultrasonic Melt Treatment
Authors: Neh Kristina , Ullmann Madlen , Kawalla Rudolf
Published: November 2016

The aim of this study is to reveal the influence of ultrasonic treatment in the molten state on microstructural evolution of the magnesium alloy AZ31 with and without the addition of SiC particles. Therefore, a heatable wedge-shaped mold for holding the magnesium melt on the required temperature was constructed with the possibility to insert an ultrasonic horn into the melt. Previously ingots of AZ31 were molten in an electrical furnace under a protective gas atmosphere. SiC particles with an average diameter of 2 μm were added to the melt. Mechanical stirring was conducted to ensure homogeneous distribution of the particles. The molten Mg was subjected to ultrasonic sound with constant frequency of 20,000 Hz and amplitude of 12.4 μm. The time of ultrasonic treatment was defined on 60 seconds. The material solidified quickly due to the cooling with water nozzles after withdrawing of the ultrasonic horn. AZ31 without SiC particles was treated under the same conditions. The resulting microstructure was observed by optical and scanning electron microscopy. Depending on resulting intensity and the effective area a refinement in grain size and also more homogeneous distribution of precipitations in the material is achieved. The resulting microstructures of AZ31 with and without SiC addition were compared and discussed.
Influence of Process Parameters on the Product Integrity in Friction Stir Extrusion of Magnesium Alloys
Authors: Baffari Dario , Buffa Gianluca , Fratini Livan
Published: November 2016

Friction Stir Extrusion is an innovative direct-recycling technology for metal machining chips. During the process a specifically designed rotating tool is plunged into a cylindrical matrix containing the scraps to be recycled. The stirring action of the tool prompts solid bonding related phenomena allowing the back extrusion of a full dense rod. This process results to be particularly relevant because allows the reuse of the scrap without any previous treatment. Experiments have been carried out in order to investigate the influence of the process parameters on the extrudes quality and a numerical model has been developed in order to simulate the evolution of the material flow.
Energy Efficient Servo Controlled Roll Levelling Machines
Authors: Sáenz de Argandoña Eneko , Silvestre Elena , Garcia Daniel , Mendiguren Joseba , Galdos Lander
Published: November 2016

The roll levelling and coil straightening facilities are becoming one of the most important process steps when forming Ultra High Strength Steels. The correct levelling and straightening of these materials are the main responsible for the stabilization of the residual stresses through the thickness and post forming springback of sheet metal formed components.Due to the arrangement of the rolls in roll levellers, micro-sliding occurs between the rolls and the sheet and the first rolls are subjected to high torques and high forces since they are responsible for the plastification of the material to a high extent. In order to reduce these drawbacks and optimize the energy consumption avoiding energy loses due to friction, the use of servo technology in levelling processes is studied in this paper.A wide range of materials are levelled using the conventional and the new servo controlled strategy that uses two servo motors and the process improvements are quantified.
Experimental Investigation on Shape Evolution in Metal Forming Hybrid Process
Authors: Makhdum Farrukh , Conway Alastair , Blackwell Paul
Published: November 2016

The feasibility of combining spinning, shear forming and flow forming processes has been demonstrated through manufacturing of a representative of a hub component using industrial scale hybrid-forming machine available at the Advanced Forming Research Centre (AFRC). The manufacturing cycle consisted of single to multiple passes of shear forming, spinning and flow forming. The research has proven that the spinning, shear forming and flow forming can be combined using a single machine with a single set of tooling and single process cycle. Circumferential and axial cracking was observed in initial set of trials which were eliminated using a series of experiments. The methodology that was used in these series of trials to remove the cracks/defects that may occur during forming of such component is presented here.
Influence of Burnishing Conditions on Burnishing Force and Application of Coated Roller in Inclined Roller Burnishing
Authors: Okada Masato , Hirokawa Takuma , Asakawa Naoki , Otsu Masaaki
Published: November 2016

The influence of burnishing conditions on the burnishing force in the inclined roller burnishing method, which was developed by the authors, is investigated. The wear behaviors of non-coated and TiN- and Diamond-Like-Carbon-coated rollers and the effect of the coated roller on the inclined roller burnishing were also investigated. A round bar of carbon steel and an aluminum-based alloy were used as the workpiece material. The burnishing force was measured by a strain-gauge type 3-component dynamometer. The burnishing force component, which acts in the circumferential direction of the workpiece, increased with increasing inclination angle of the roller. Improvement of the tool life of the roller was obtained with a TiN-coated roller on which nitriding treatment of the base roller was performed prior to TiN coating. A satisfactory burnished surface was obtained by burnishing with the DLC-coated roller.
Investigation of the Relationship between Material Flow and Rollover in Double-Sided Shearing Using Image Processing
Authors: Sasada Masahiro , Tamura Jun
Published: November 2016

Shearing is the cutting of a sheet material with a punch and a die. The cut surface obtained by shearing is composed of rollover, a sheared surface, a fracture surface and burr. It has been reported that rollover is formed by the insufficiency of material and material flow in the lateral direction. However, the rollover in the sheet material on the die and that in the sheet material under the punch have not been evaluated individually in previous studies. In this report, the relationship between the material flow and the formation of rollover in the sheet material on the die is discussed on the basis of experimental results obtained by image processing. The relationship between the material flow and the formation of rollover in the sheet material under the punch also is discussed. Double-sided shearing with a counter punch was carried out. The deformation of the sheet material was observed through reinforced glass using a high-speed CCD camera. The image processing was carried out to investigate the material flow. The results were as follows. When the clearance is small, the material flow in the clearance is toward the sheet material on the die. When the clearance is large, the material flow in the clearance is toward the sheet material under the punch. The area of rollover in the sheet material on the die is equal to the sum of the amount of material flow in the clearance and that in the lateral direction. On the other hand, the area of rollover in the sheet material under the punch is equal to the sum of the amount of material flow in the lateral direction under the punch, that in the clearance and the insufficiency of material. These findings are useful for considering the relationship between the material flow and the formation of rollover in the case that the rollover in the sheet material on the die and that in the sheet material under the punch are evaluated individually.
Manufacture of Magnesium Tubes with Gradient Hardness Distribution Using a Two-Stage Porthole Extrusion Die
Authors: Hwang Yeong-Maw , Chen Yu , Alexandrov Sergei
Published: November 2016

This paper aims to manufacture magnesium alloy tubes with gradient hardness using hot extrusion process. A two-stage porthole die together with a mandrel is designed to have a straight channel part combined with a conical part. Materials are pushed through this specially-designed die cavity to generate a non-uniform velocity distribution at cross sections between the mandrel and the die and result in different strain and strain rate distributions. Accordingly, a gradient microstructure or hardness product can be obtained. Using the finite element analysis, the effective strain distributions inside the die cavity and at the die exit are firstly discussed for various inclination angles in the conical part of the mandrel. Then, hot extrusion experiments with a two stage porthole die set are conducted to obtain magnesium alloy products with gradient microstructures and hardness. Using a die set of mandrel inclination angle of 10o and die inclination angle of 25o, gradient microstructures of grain sizes of 4.30μm, 5.92 μm and 3.67μm at the outer surface, center zone, and inner surface, respectively, are achieved.
An Analytical and Numerical Investigation on Flange Wrinkling Behavior in Warm Forming Process of AA5754 Using Macro-Textured Tool Design
Authors: Zheng Kai Lun , Zhu Lei , Politis Denis J. , Lin Jian Guo , Dean Trevor A.
Published: November 2016

In this paper, an analytical buckling model is established to predict the flange wrinkling behavior of deep drawn cylindrical cups of aluminium alloy sheet in warm forming conditions using macro-textured blankholders for the first time. A continuum damage mechanism (CDM) based material model was utilized to reflect the visco-plastic feature of material at elevated temperatures. Forming speed and temperature effects were investigated, and texture ratio and draw ratio effects were also discussed. The developed analytical buckling model was validated by finite element simulations. The increase of forming temperature and forming speed is prone to cause wrinkling for AA5754, but the effects are not as significant as the texture geometry and draw ratio. The analytical model presented in this paper can be used as a design guide to determine tool texture geometry necessary to avoid wrinkling defects in the warm forming processes of aluminium alloy.
A New Method Predicting Contact Length and Flattening in Temper Rolling
Authors: Ilmola Joonas , Pohjonen Aarne , Larkiola Jari , Nylander Jari
Published: November 2016

The current trend in temper rolling is to make a small reduction to steel strip in order to achieve higher strength with good formability and toughness. In addition, very high strength steels can be cold rolled twice with very small reductions. This causes problems in setup values for cold rolling. Rolling models are usually overestimating roll flattening in the case of small reductions.In temper rolling thickness reduction is small (0.5 – 3%) and the elastic deformation of the work roll should be taken into account [3]. However, standard circular arc roll gap models (e.g. Bland Ford Ellis combined with Hitchcock model) fail to predict the roll flattening and thus the rolling force [4]. In this work, finite element method has been used to define a simplified model for work roll flattening and contact length. Model describes the effect of reduction, strength of steel strip and roll radius.
Constitutive Equation Development to Model the Hot Forging of ZERON®100 Super Duplex Stainless Steel and Associated Microstructural Evolution
Authors: Pennington Jamie , Wynne Bradley P. , Byrne Glenn
Published: November 2016

A constitutive equation of flow stress based on the Norton-Hoff equation has been developed for the high chromium and nitrogen containing super duplex stainless steel, ZERON® 100 (UNS S32760). This was then used to model, using the finite element method, the strain distribution within a uniaxial compression test under typical two-phase forging conditions. Predictions from the model were used to correlate deformation history to microstructure morphology. The microstructure consisted of austenite, γ islands (both primary and secondary) within a ferrite, δ matrix that contained chromium nitride precipitates. For deformation temperatures of 1050°C and 1120°C, the small secondary austenite was equiaxed, whilst at 1280°C the secondary austenite exhibited a Widmanstätten morphology. The highest level of nitride precipitation occurred at the highest deformation temperatures, i.e. highest volume fraction of ferrite, independent of strain rate. This suggests that nitride precipitation appears to be driven to a greater extent by thermal factors than deformation substructure.
Finite Element Simulation of Heat Transfer during Cryogenic Asymmetric Sheet Rolling of Aluminum Alloys
Authors: Pesin Alexander , Pustovoytov Denis
Published: November 2016

Aluminum and its alloys are widely used as structural materials in aerospace, automotive and other industries due to low density and high specific strength. Efficient way to increase strength and other properties of aluminum alloys is to form an ultra fine grain structure using severe plastic deformation methods. Cryogenic asymmetric sheet rolling under liquid nitrogen temperature is a process of severe plastic deformation that can be used to improve the aluminum alloys structure and properties. Prediction of sheet temperature during plastic deformation is very important. The temperature of sheet is changed due to the conversion of mechanical work of deformation into heat through sliding on contact surfaces. This paper presents the results of the finite element simulation of heat transfer during cryogenic asymmetric sheet rolling of aluminum alloy 6061. The effect of thickness reduction, rolling velocity and friction coefficient on the deformation heating and temperature field of aluminum alloy 6061 was found. The results of investigation could be useful for the development of the optimal treatment process of aluminum alloys by cryogenic severe plastic deformation to obtain the ultra fine grain structure and high strength properties.
Numerical Modelling of AlSi7 Tubular Components Flowformed at Elevated Temperature
Authors: Novella Michele Francesco , Ghiotti Andrea , Bruschi Stefania , Capuzzo Riccardo
Published: November 2016

In small batch manufacturing, flowforming may represent an optimal semi-finishing process for axisymmetric parts, due to its versatility, the reduced material waste, the good geometrical tolerances as well as the improvement of the mechanical characteristics it allows to attain. However, the main limiting factor often lies in the lack of knowledge for the process design, which implies expensive industrial trials often based on trial-and-error approaches. Due to these reasons Finite Element (FE) numerical simulation can provide a significant help in the design and management of the process, but its application is still facing relevant issues, mainly linked to: (i) the complex contact conditions between tooling and part, (ii) the high computation effort due to the 3D geometry rotating at high speed, and (iii) the complex strain paths that the material undergoes.The paper presents an optimized FE model of the flowforming process of AlSi7 alloy tubular components carried out at elevated temperature. An implicit solution scheme and an arbitrary Lagrangian-Eulerian meshing was adopted, while the constitutive parameters of the material model were calibrated on the basis of experimental compression tests carried out in the same thermo-mechanical conditions of the industrial reference process. The influence of the main process parameters, namely thickness reduction, feed rate and mandrel rotation speed were investigated and an algorithm for parametric process charts derivation was finally proposed.
An Investigation of Direct Powder Forging of Nickel Superalloy FGH96
Authors: Fang Shuang , Shi Zhusheng , Bai Qian , Jiang Jia Ying , Wang Shu Yun , Lin Jian Guo
Published: November 2016

Powder metallurgy (PM) nickel-based superalloy has been widely used in high temperature applications and is most commonly manufactured using hot isostatic pressing (HIP). However, HIP is an expensive process and takes a long time at high temperature which leads to the formation of networks of prior particle boundaries (PPBs). In this study, a recently developed processing method - direct powder forging (DPF) was employed to produce a PM nickel-based superalloy component, using a single acting hydraulic press under normal atmosphere. EBSD study has been conducted for its microstructure, grains size distribution, and grain boundary misorientation; and mechanical testing has been carried out for its hardness and tensile properties at room temperature and 650°C. It has been found that the DPFed material has reached full density in the whole component. Networks of PPBs have been broken in the direct powder forged FGH96 alloy. Compared with HIPed FGH96 alloy, the DPFed material has a substantially higher recystallisation nucleation degree and more recrystallised sub-grains. After heat treatment, the tensile properties of the direct powder forged FGH96 alloy match or surpass those of the material produced by HIP plus isothermal forging.
Exploitation of Field-Assisted Sintering Technology (FAST) to Produce Pre-Forged Billets from Metastable Beta Titanium Alloy Powder
Authors: Calvert Emma , Wynne Bradley P. , Jackson Martin
Published: November 2016

Powder produced by gas atomisation of metastable beta alloy Ti-5Al-5Mo-5V-3Cr has been consolidated using field-assisted sintering technology (FAST) to examine the suitability of the process to produce pre-forged billets as opposed to the conventional multi-step Kroll-VAR-forging route. FAST testing was performed using an FCT Systeme GmbH spark plasma sintering furnace type HP D 25 at The University of Sheffield. The dwell temperature was varied between 800 and 1200°C and the dwell time between 3 and 60 minutes. The process was found to allow very precise control over the beta grain size in Ti-5Al-5Mo-5V-3Cr by variation of the dwell time and dwell temperature, producing grain sizes between ~40 and ~350 μm. However, it was found that the grain size was increased more by increasing the dwell temperature than increasing the dwell time. The porosity was found to be between 99.5 and 100 % for all dwell temperatures at dwell times of 30 minutes or above. FAST has the ability to produce almost fully consolidated Ti-5Al-5Mo-5V-3Cr pre-forged material from powder with a controlled beta grain size, which is not possible by other methods.
Investigation on the Mechanical Properties and Formability of Ti3Al2.5V Tubes Deformed at Elevated Temperatures
Authors: Simonetto Enrico , Venturato Giulia , Bruschi Stefania , Ghiotti Andrea
Published: November 2016

Titanium and titanium alloys are largely used in aircrafts to manufacture piping and structural components, thanks to the high strength-to-weight ratio and the excellent corrosion resistance. However, despite the advantages in terms of mechanical and chemical performances, they present significant limits when shaped at room temperature due to the high strength and the low ductility. The use of temperature-assisted processes might represent an interesting option to overcome the above-mentioned limitations, although the effects on the microstructural and chemical properties should be accurately considered.The paper presents the results of investigations on the Ti3Al2.5V alloy, carried out to evaluate the influence that the thermal cycle parameters have on the mechanical properties and microstructural characteristics of tubes draw bent at elevated temperatures. Tensile tests at elevated temperatures have been performed on specimens directly cut from tubes in order to get the flow-stress curves and elastic material properties. With reference to typical industrial process conditions, different heating rates and soaking times were tested to analyse the influence on the microstructure, namely the grain size, the precipitation of secondary phases and superficial oxidation. Scanning Electron Microscopy and micro-hardness measurement techniques were used to assess the post-forming characteristics at different temperature and strain rate conditions.
Formability and Surface Quality of Incrementally Formed Grade 1 Titanium Thin Sheets
Authors: Formisano Antonio , Boccarusso Luca , Carrino Luigi , Durante Massimo , Langella Antonio , Minutolo Fabrizio Memola Capece , Squillace Antonino
Published: November 2016

The incremental forming of titanium alloy sheets combines the advantages of this advanced flexible manufacturing process, that allows to produce complex components without using dedicated tools, with the interesting properties of the material under consideration. In this study, thin sheets of grade 1 titanium were incrementally formed to evaluate their formability and surface quality by varying the tool-sheet contact conditions. Experimental tests and surface analyses highlight dependence on the contact conditions of the surface quality rather than of the formability. Moreover, they emphasize that the tool-sheet contact conditions mainly affect the repeatability of the process due to the occurrence of galling.
Compressive Properties of Rock Mass with Horizontal Weak Interlayer
Authors: Li Jian Guang
Published: November 2016

Rock mass with horizontal weak interlayer is studied on, and similar material standard samples with layers were made by using self-made device. Some conclusions are obtained by uniaxial compression experiments: both the strength and elastic modulus of rock mass decrease with thickness of weak interlayer increasing; for constant total thickness, both the strength and elastic modulus of rock mass increase with the layer number increasing, and the mathematical relationship between the strength and interlayer thickness and layer number of rock mass is given. Once compressive properties of rock mass with horizontal interlayer is obtained, researcher can get those of rock mass with dip interlayer by coordinate transformation further, and can predict the whole stability of engineering structure with weak interlayer in different situation.
A Study of Creep Similarity Criterion of Soft Rock in Temperature-Stress Environment
Authors: Ma Zhen Guo , Wang Yong Yan
Published: November 2016

Model experiment is a method to study the creep deformation and failure mechanism of soft rock under complicated geological conditions. The similar criterion is the theoretical basis of Model Experiment. This paper used dimensional analysis to deduce the similarity criterion in elastic and creep stage of deep soft rock Model experiment. We got the Model experiment similarity index compliance by studying the similarity criterion. This provides a theoretical basis to study the creep properties of soft rock.
Effects of Foaming Temperature on Super Light Particles of Polypropylene Prepared by Batch Method
Authors: Zhang Cong , Qin Liu , Yu Hua Chun
Published: November 2016

Super light micro foam particles of isotactic polypropylene (IPP) is prepared by the process of rapid evaporation method. The experiment uses three different heating methods which are oven, water bath and glycerol bath, respectively. The IPP’s foaming temperature is also different. The density of micro foam particles is tested. As a result, the micro foam IPP of different density and corresponding foaming temperature range can be got. The density of micro foam particles is reduced 32% than original particles. The IPP’s characteristics of micro foamed are described on different foaming temperature and different heating methods. At the same time, the reasons of different characteristics are also explained.
Formation and Evolution of Chemical-Physical Complex Network during Vulcanization in Carbon Black Filled Natural Rubber (NR)
Authors: Yu Guang Shui , Liu Ji Wen , Cheng Jun Mei , Sun Chong
Published: November 2016

The formation and evolution of chemical-physical complex network during vulcanization in carbon black (CB) filled NR was investigated in this work. The results showed that the cross-linking density increased with increase of CB content. The variation of torque during vulcanization was attributed to crosslinks of macromolecular chains. The critical content of CB for the forming of CB network was between 30phr and 40phr (weight percentage). The CB content did not affect the glass transition temperature (Tg) obviously.
Study on Flexible Fatigue Properties of Nature Rubber with Different Styrene-Butadiene Rubber
Authors: Liu Wei , Bao Zhong Cun , Zong Cheng Zhong
Published: November 2016

Flexible fatigue properties is an important property of rubber, it can reflect the service life of rubber products. Different types of SSBR were used in the vulcanized rubber with NR contributed different to the flexible fatigue properties. In this paper, 5 different types of SSBR with special structure were used to study the mechanical properties, thermal properties and the flexible fatigue properties. In a result, with different types SSBR, the vulcanized rubber show different basic mechanical properties and flexible fatigue properties, but little effect to the hardness and stretching stress. Above all these SSBR, RC2564S is the best which contribute to flexible fatigue properties.
Design of a Plastic Auto’s Door Based on the Rotational Molding Process
Authors: Shan Ti Kun , Chen Cheng Tao , Huang Jing Dong
Published: November 2016

In order to reduce the weight of the car, which made molded plastic door through rotational molding process. According to characteristics of rotational molding process, design plastic doors structure using UG software. By contrast the design of traditional sheet metal door, introduces the rotational molding process several key technologies of structure design of door from the simple molding, doors internal strengthening of structures and accessories.
Influence of Die Casting Temperature and T1 Treatment on the Microstructure and Properties of the Alsicumg Alloy
Authors: Wei Li Jun , Li Bo Long , Guan Liu Yi , Wang Tong Bo , Qi Peng , Nie Zuo Ren
Published: November 2016

Al-Si alloy was widely applied in automobile engine parts to realize weight reduction. The influence of casting temperature on the microstructure of die casting Al-Si-Cu-Mg alloy was studied in this paper. Based on ZL 101 alloy, the strength was improved with addition of 0.8% Cu element. The influence of pouring temperature on microstructure was investigated using optical microscope and electron probe micro-analysis (EPMA), and T1 heat treatment was optimized. The primary α-Al was more coarsened when the pouring temperature rose from 660 ̊C to 690 ̊C. The solid solubility of Cu in α-Al was 0.2406 wt%, analyzed by EPMA. Considering the solid solubility of Cu and avoiding porosity at high-temperature, T1 heat treatment was reasonable and affective. The micro-hardness reached to a peak value of 114 HV during aging at a temperature of 175 ̊C after 10 h. Therefore, 175 ̊C×10h aging was the most appropriate heat treatment process.
The Effect of Cryorolling on the Microstructure of Al-Cu-Mg Alloy
Authors: Quan Li Wei , Mu Wen Ning , Kang Lei , Ma Xiao , Han Peng , Huang Ming Li
Published: November 2016

A precipitation hardenable Al-Cu-Mg alloy was cryorolled with liquid nitrogen followed solution treatment and then aged at 170 ̊C for different time. The microstructure was characterized by optical microscopy (OM) and transmission electron microscopy (TEM). Hardness and tensile strength were also tested. The dislocation loops in the cryorolled alloy are more than the room temperature rolled alloy. Meanwhile the hardness, yield strength and tensile strength are larger than the room temperature rolled alloy.
Effect of Cooling Rate on Modification and Grain Refinement of 4032 Aluminum Alloy
Authors: Wu Yong Fu , Zhu Guang Lei , Zhong Gu , Nagaumi Hiromi
Published: November 2016

Effect of cooling rate on modification and refinement of 4032 aluminum alloy has been investigated at cooling rates of 0.7~4.5 K/s. Sr is used to modify eutectic silicon and B is used to refine primary α-Al grains. Modification level of eutectic silicon and refining results of primary α-Al are characterized quantitatively by Lp based on the perimeter of eutectic silicon particles and the maximum grain length D, respectively. As the cooling rate decreases, the needle-like eutectic silicon particles increases and the modification level reduces with a constant Sr content. Influenced by alloying elements such as Mg, Cu and Ni, the modification level is very low at the lowest cooling rate of 0.7 K/s, but properly increasing Sr content in the melt can improve the modification. At the cooling rates of 0.7~4.5 K/s, the element B can transform coarse columnar dendritic α-Al grains to equiaxed ones, and controlling the ratio of Sr and B is a valid technique to avoid mutual poisoning. On the conditions of present experiments, the Sr content of 350 ppm and Sr:B ratio of about 1.1 are rational to modify eutectic silicon and refine primary α-Al grains simultaneously.
Abnormal Effects of Temperature and Strain Rate on the Ductility of a Carbon Nanotubes Reinforced Al Alloy Composite
Authors: He Wei Jun , Li Chun Hong , Li Zhi Qiang , Luan Bai Feng , Liu Qing
Published: November 2016

Carbon nanotubes reinforced aluminum alloy (CNTs/Al alloy) composite was fabricated by the method of flake powder metallurgy. With Gleeble-3500 system, hot compression tests at different temperatures and strain rates were conducted to investigate the effect of temperature and strain rate on the deformation behaviors of the CNTs/Al alloy composite. Experimental results show that the composite’s ductility is worse at higher deformation temperature within range of 300 oC-450 oC. Additionally, the composite’s ductility is better at higher strain rate, which is against general knowledge. The microstructure before and after deformation were characterized by SEM and TEM. It demonstrates that the grain size of the composite is always in the nanoscale. The abnormal effects of temperature and strain rate on the ductility may be explained by the evolution of work hardening capability at different deformation conditions.
Quantitative Phase Analysis of Aluminium-Lithium Alloys
Authors: Betsofen Sergey , Antipov Vladislav , Knyazev Maxim , Dolgova Margarita
Published: November 2016

A quantitative approach to the determination of the phase composition in the Al-Mg (Cu)-Li alloys has been developed on the basis of the balance equations of chemical and phase compositions as well as the lattice parameter measurement of the α solid solution. It is shown that, for the Al-Mg (Cu)-Li alloys, the ratio between the fractions of the δ' (Al3Li) and S1 (T1) phases is determined by the ratio between the molar fractions of Li and Mg (Cu). By means of this technique it is shown that in Al-Cu-Li alloys the proportion of δ'-phase is much higher than ternary T1-phase, and the proportion of δ'-phase and a ternary phase (S1) are approximately equal in alloys of Al-Mg-Li system. The equations for the calculation of the contents of the S1 (Al2MgLi), T1 (Al2CuLi) and δ' (Al3Li) phases in the 1420, 1424, 5090 alloys (Al-Mg-Li alloys) and in the 1440, 1441, 1450, 1460, 1461, 1464, 1469, 2050, 2090, 2091, 2094, 2098, 2099, 2195, 2198, 2199, 2297, 8090 (alloys (Al-Cu-Li alloys) are given.
Study of Texture in 6016 Aluminum Alloy during Processing
Authors: Wen Zhang , Liu Ying Ying , Jia Zhi Hong , Zhao Pi Zhi , Zhang Zhi Qing , Liu Qing
Published: November 2016

The evolution of texture in AA6016 alloy during processing was systematically investigated. The hot-rolled 6016 plates were cold-rolled to 0.9mm through three different rolling processes. One was directly rolled to 0.9mm, the other two were rolled to 1.8mm and 2.3mm, respectively, followed by intermediate annealing at 360°C for 2h, and then rolled to 0.9mm. Finally, the three kinds of cold rolled plates were performed continuous annealing at 560oC. The textures and microstructures of each stage were characterized by the X-ray diffraction and electron back scattering diffraction (EBSD) techniques. The results show that the texture of hot-rolled sample is mainly composed of Brass, S and Copper; the relative amount and maximum density changed after 1st cold-rolling. After intermediate annealing, the Cube and Cube+ND20 texture replace the deformation texture and rise with the rolling reduction. Then the conducting of final cold rolling results in the decrease of Cube and Cube+ND20 component and increase of deformation texture. After the continuous annealing, R, Brass-R, Goss, Cube and Cube+ND20 components are observed. Particle stimulated nucleation (PSN) and nucleation at shear bands dominate the competition of recrystallization.
Micro Structural Changes in Welded AlCuLi-Alloys by Positron Annihilation Spectroscopy, SAXS and DSC
Authors: Petschke Danny , Staab Torsten E.M.
Published: November 2016

We follow changes in the micro structure at several distances from the weld nugget of friction stir welded AlCuLi-alloy (AA2198) plates occurring due to the tool movement and the created heat by employing different methods: Small Angle X-ray Scattering (SAXS), giving information on type, size and density of precipitates, Differential Scanning Calorimetry (DSC), giving information on formed precipitates by their dissolution signal, and positron annihilation lifetime spectroscopy (PALS), being sensitive to vacancies and dislocations as well as to the formation and growth of precipitates. We start by characterizing the base material as a reference and proceed via the heat-affected zone to the weld nugget. By the use of complementary methods, we obtain information on structure, kind and distribution of precipitates and correlate this with hardness measurements.