Zur Leitfähigkeit von mehrphasigen Werkstoffen — Vergleich zwischen experimentellen und berechneten Werten von Cermets —

The Conductivity of Cermets and other Multiphase Materials — Comparison between experimental and calculated electrical Resistivities. It was pointed out in the other two parts of this work, which equations amongst more than fifty enable the calculation of field properties (e. g. electrical and thermal conductivity, magnetic permeability) of multiphase materials (including porous materials) from microstructure parameters on a physical basis. Their derivation has been considered as well.—These ?stereometric functions of field properties”? are summarized here revealing the relation between the properties of multiphase materials and the concentration, shape, orientation and properties of their constituent phases. — These equations are used now for calculating the electrical resistivity of cermets. Experimental values of about fifty various cermet combinations are compared with theoretical curves. The theoretically predicted dependence of the electrical resistivity on concentration, shape, orientation and temperature is clearly confirmed. Consequently the field properties of multiphase materials can be calculated from their stereometric microstructure data and field properties of their constituent phases. This helps in all cases, where, under certain conditions very low accuracy is to be expected from direct measurements, or when the microstructure can be more easily determined. Furthermore these equations show the direction in which the microstructure should be improved to achieve optimal properties (tailor made materials). Finally, these equations provide a means to avoid cumbersome data collections on multiphase materials, once the properties of the phases are well known.     

Optoelectronic properties of Cr-substituted II–VI semiconductors

Materials with an isolated partially filled intermediate band are of great interest as new materials for high-efficiency solar cells because of the properties of this band. This intermediate band is only present in some compounds. The study presented in this work is based on X₃₂Zn₃₁Cr materials where X = S and Te. The electronic properties, atomic and orbital composition of these materials, population analysis and optical properties have been calculated and analyzed. The absorption coefficients show an increase in the absorption sub-gap as a consequence of the optical transitions between the valence band and this partially filled intermediate band, and with lower importance, due to the transitions between the intermediate and the conduction band. These transitions could lead to an increase in solar conversion efficiency.     

Obituary – Dennis Hine

It is with regret that we record the death of Dennis Hine on 15 June 2007 at the age of 80. Hine joined the Packaging and Allied Trades Research Association (which subsequently became Pira( at the age of 27 and remained with Pira until his retirement. Hine was a gifted scientist with a natural interest in understanding the world around him. He pioneered the development of test instruments that simulated and quantified packaging machine operations, for example, adhesive bonding, film runnability, crease stiffness and carton opening. Test instruments designed by Hine continue to be manufactured and sold around the world. He is particularly noted for his research on carton quality and machine–material interaction during the 1960s and the 1970s. His research reports in this field continue to be cited, and he was awarded a fellowship at the Institute of Packaging in recognition of his contribution to packaging science. The understanding of carton quality developed by Hine is widely applied today and is the basis for the only national standard for crease quality. As well as authoring many technical reports and papers, in his retirement Hine also wrote the textbook Cartons and Cartoning. Hine was awarded a special degree in physics by the London University in 1947, and then worked during the later war years at the Research Association of British Rubber Manufacturers in Croydon on war‐related work. After the war, he was allowed to present his work as a thesis, for which he was awarded a master's degree. Hine had a genuine fascination with understanding the world around him, and he approached research and investigation with enthusiasm tempered only by a highly structured and analytical approach. These qualities can be seen in his personal as well as professional life through his final years, where he took a serious interest in understanding the treatment of his cancer. Dennis Hine is survived by his wife Grace, his three children and four grandchildren.     

Untersuchungen über die Bestimmung der Zähigkeit von Bauteilen im Apparatebau durch Messungen an Modellbehältern von praxisähnlicher Größe. Versuche mit Behältern aus Kesselblech H 1 bei Temperaturen −80°C

Research into the Determination of the Ductility of Structural Elements in Plant Construction by Measurement on Model Vessels of Near Industrial Size— Tests on Boiler Plate Vessels (Kesselblech H 1) at Temperatures Down to ?80°C The paper deals with a research program of the Dechema working group “Materials for Chemical Apparatus”, by which an attempt is made to correlate ductility as a characteristic materials property with ductility changes to be expected in structural elements and structures. On a low temperature test stand model containers are loaded internally until bursting and the deformations of a container bottom having a complex shape are measured. Deformation and bursting pressure vs. temperature support the preliminary conclusion that the embrittlement temperature for such structures is lower than the notch toughness transition temperature of the material. Corroboration of this finding requires further work with other materials and structures.     

Innovative façade technology using masonry – Solid construction 2.0 / Innovative Fassadentechnik mit Mauerwerk – massiv construction 2.0

This article illustrates the solid building envelope both as an integral system and in terms of its potential for additive manufacturing. The Façade Research Group at the TU Delft works on the building envelope, investigating strategic and process support for development and planning processes and renovation technologies, as well as functionally integrated building envelopes. The Institute of Structural Mechanics and Design at the TU Darmstadt undertakes research and development in the areas of materials technologies (glass, polymers) and additive manufacturing as they relate to building structure.     

Reaktives Diffusionslöten von Keramik an Stahl mittels Zr–Cu–Zr‐ und Zr–Ni–Cu–Zr‐Schichten für Anwendungen im Hochtemperaturbereich

Joints manufactured by transient liquid phase bonding feature comparable properties as diffusion weldements, but considerably lower process temperatures and pressures have to be applied. The liquid phase, which is hereby used, occurs due to interdiffusion between the base and/or the filler materials at a constant temperature, which lies below the melting temperature of the substrates. An essential requirement for this diffusion‐based melting is that the involved materials have low melting alloy‐constitution areas, such as eutectics. The aim of the study, presented in this contribution, is to evaluate an approach, in which an active transient liquid is created by suitable interlayers, in order to facilitate the wetting of ceramics. The potential of this attempt will be illustrated on zirconia/stainless‐steel‐joints for high temperature applications, such as solid oxide fuel cells. In such applications, the used materials have to withstand harsh conditions, e.g. high operating temperatures, oxidizing or reducing environments, which represent a demanding challenge for joining technologies, even at the latest state of research. In this study interlayers, consisting of Zirconium, as the active element, in combination with Copper and/or Nickel, have been investigated. These systems exhibit a wide range of alloy‐constitutions with low melting temperatures, which can be used for the formation of the transient liquid phase. For the application of the interlayers, physical vapor deposition as well as 75 µm‐thick Nickel‐foils have been used. The joining was carried out in high vacuum with changing holding times and temperatures. Additionally, the ratio of the thickness of the used interlayers was changed. Results of microstructural investigations, nano‐hardness measurements of the joining area as well as shear strength and fractography are presented.     

Metal–Organic Framework (MOF)‐Based Drug/Cargo Delivery and Cancer Therapy

Metal–organic frameworks (MOFs)—an emerging class of hybrid porous materials built from metal ions or clusters bridged by organic linkers—have attracted increasing attention in recent years. The superior properties of MOFs, such as well‐defined pore aperture, tailorable composition and structure, tunable size, versatile functionality, high agent loading, and improved biocompatibility, make them promising candidates as drug delivery hosts. Furthermore, scientists have made remarkable achievements in the field of nanomedical applications of MOFs, owing to their facile synthesis on the nanoscale and alternative functionalization via inclusion and surface chemistry. A brief introduction to the applications of MOFs in controlled drug/cargo delivery and cancer therapy that have been reported in recent years is provided here.     

Oxidation protective coatings for γ‐TiAl – recent trends

Engine designers show continued interest in γ‐TiAl based titanium aluminides as light–weight structural materials to be used at moderately elevated temperatures. Although alloy development has made significant progress in terms of mechanical properties and environmental resistance, protective coatings have been developed that help to extend the lifetime of these alloys significantly. The major challenge of coating development is to prevent the formation of fast growing titania. Furthermore, changes of coating chemistries at high temperatures have to be considered in order to avoid rapid degradation of the coatings due to interdiffusion between substrate and coating. The paper describes recent work of the authors on different coatings produced by means of magnetron sputter technique. Thin ceramic Ti‐Al‐Cr‐Y‐N layers tested at 900 °C exhibited poor oxidation resistance. In contrast, intermetallic Ti‐Al‐Cr, Si‐based and aluminum rich Ti‐Al coatings were tested at exposure temperatures up to 950 °C for 1000h resulting in reasonable and partially excellent oxidation behaviour.     

Talking about Torque: Measuring Pack Accessibility – a Review

Vacuum lug closures are a simple, reliable and low‐cost packaging option used for the protection and promotion of jams, pickles and sauces. Several surveys and anecdotal evidence suggest that packaging of this type can be notoriously difficult to open. Given the difficulty that packaging of this type may pose, there has been significant academic research in understanding the difficulties associated with accessing packaging of this type. In response to the qualitative data gathered in these surveys, research teams have attempted to quantify the forces that users can apply. What emerges from the approaches taken is a complex picture. Researchers do make comparisons with previous work, but numbers of people tested, materials used, diameter and posture differ between research groups as does the information and style of the dissemination of results. Future packaging research experimental design should be more thorough and consistent in the sampling and presentation of data to facilitate repeatability and validity and enable the data gathered to form a larger data set. Further, to create usable ‘design limits’ for manufacturers and designers to reduce the variability within the data set, more focused measurements should be taken on distinct user groups such as a specific female decile and subgroup, i.e. small‐handed women between 70 and 80. Working with distinct populations would enable the likelihood of design changes to packaging to be readily compared and assessed. Copyright © 2014 John Wiley & Sons, Ltd.     

Target Costing für Werkstoffe – Potenziale und Methodik

Target Costing for Materials – Potentialities and Methodology Target Costing is a standard instrument of cost management in business administration, but hardly mentioned in the economic oriented literature on material sciences. Nevertheless there are high potentialities for developers, producers, or users of materials regarding the improvement of efficiency. Therefore, this article will present these potentialities of a material oriented Target Costing. Besides, the general methodology of Target Costing will be modified to meet the specifics of materials from the perspectives of users of materials on the one hand and developers respectively producers of materials on the other.     

Umformtechnologie: Prozesse – Werkstoff‐ charakterisierung – Simulation – Verifikation

Sheet forming technology – processes, materials, simulation and verification Hydroforming and Deep Drawing represent leading technologies for forming sheet metal components. The Materials Branch of the University of Duisburg‐Essen works since more than 10 years in the field of Hydroforming and showed that Hydroforming increases the strength and that the weldings of hydroformed tubes normally exhibit a same (fatigue) strength as the base material. For an improvement of the economics of hydroforming spliced tubes were considered and standard hollow nodes for tubes nodes structures were developed and a proposal was made to produce these tubes in variable tools with segments or lamellas. A significant increase in economics of Hydroforming and of Deep Drawing of components is achieved by an introduction of the principles of an integral (cooperative) development of products. At the University of Duisburg‐Essen the following stages are run through: CAD (the Material Branch uses PRO/ENGINEER®), forming simulation – for that PAM‐STAMP® (ESI) and PATRAN MARC MENTAT® (MSC) are used – FEM strength calculation and EVICD for a consideration of variable service loading. Forming simulation needs as basic material data the yield curve, the parameters of anisotropy and the Forming Limit Curve (FLC). For a determination of the FLC in Deep Drawing Tests suitable Nakazima specimens were developed by applying the principles of cooperative product development. The specimens could then successfully be validated in Deep Drawing Tests, which were instrumented by the advanced 3D‐forming‐analysis‐system AUTOGRID inProcess (VIALUX). Various other forming simulations were also performed and some general rules for the performance of forming simulations were formulated. Finally, reverse engineering is briefly discussed.     

Werkstoffanwendungen von Stahl im Zeitstandbereich – technische Herausforderung mit Langzeitwirkung

Application of creep resistant steels – A technical challenge with long‐term importance The development activities for creep resistant steels based on joint research programs in Germany and Europe have resulted in significant progress for materials application in the power plant area. Steels of 9‐11 %CrMoV are already used in operating power plants and will be applied in the planned next generation plants. In particular, the results of these newly developed steels show that a reliable long‐term extrapolation of the creep‐rupture strength is only possible on the basis of real long‐term tests and microstructural understanding. Three material examples of current relevance, P92, T122, HR1200, are given to show the reasons for and the effect of the reduction of an extrapolated 100,000h creep rupture strength. Finally, the paper deals with an example of software development for residual life estimation of CrMoV materials, developed with the results of more than 20 years of research work.     

Elektronenstrahlschweißen an Atmosphäre – von der Entwicklung bis zum industriellen Einsatz

Non vacuum electron beam welding – from development to industrial application Attributable to the increasing degree of standardisation in many fields of industrial manufacturing, the saving of resources and thus the demand for light weight constructions and also the rapid development on the material sector have made joining tasks increasingly complex. This involves the joining method which must meet the metallurgical demands of the base materials to be welded and also the method’s profitability. In this connection, electron beam welding in atmosphere – NV‐EBW ‐ as a joining method is getting more and more important and is, from the side of the industry, becoming increasingly popular. NV‐EBW combines the many, well‐known advantages of electron beam welding in vacuum with the possibility to work under normal ambient pressure. With an equipment efficiency of more than 50 % and very high, achievable welding speeds of up to 60 m/min for aluminium materials, the electron beam in atmosphere is an efficient and profitable tool for welding. Under the direction of Professor U. Dilthey, the ISF has for many years and in close contact with industrial partners carried out research work in the field of the NV‐EBW technology. At that, elementary contribution to the development of rotationally‐symmetrical orifice assemblies and also to the testing and optimization of the method with regard to respective welding tasks has been carried out.     

Glas,Glasuren, Email und Lack: Gebiete paralleler Forschung von gegenseitiger modellmäßiger Bedeutung

Glass — Glazes — Emaille and Lacquer: Areas of research in parallel with a significant working model. — A phenomenological survey of the interfacial surface energy behaviour of liquid materials applied as thin coatings. Initial observations with molten glass have drawn attention to the interfacial surface energy behaviour of other materials during their technological processing. The extensive parallelism observed during formations of largely undesirable honeycomb structures associated with thinly applied coatings suggests reason for undertaking research concerning the morphology this and related phenomena. It is intended that a summary be written to report this research.     

Design and study on a 1–3 anisotropy piezocomposite sensor

A design method is presented for 1–3 anisotropy piezocomposite so as to differentiate each strain component when it is used as the sensor in smart materials and structures. The 1–3 piezocomposite has been tailored to anisotropy by matching the scales of the piezoelectric phase and the non-piezoelectric phase. The composite samples have been fabricated by an aligning–casting–slicing process and the piezoelectric properties of the composites in the x and y directions have been measured and analyzed physically. It is shown that the difference of the piezoelectric properties of the composite between the x and y directions is up to approximately 40%.     

Nanotechnology – Markets & Trends. Nanotechnologie – Märkte und Trends

The world of nanotechnology is gaining more and more interest from the scientific point of view as well as for industrial applications. Promising product and process innovations that are based on nanotechnology have stimulated the involvement of industry and the financial community. Rather than an evolutionary oriented top‐down approach pushing critical dimensions from microns down into the nanometre range, the real potential of nanotechnology lies in the creation of novel functional structures of superior performance by controlling structures on a scale between 1 and 100 nanometres with completely changed properties. Making use of these novel properties of known materials is highly attractive for applications in a variety of fields, underlining that nanotechnology is regarded as key technology of the 21st century a promising product and process innovations that are based on nanotechnology have stimulated the involvement of scientific community and the industry, because nanotechnology is not only scientific artwork but is currently used in a considerable number of products in a multibillion‐dollar marketplace.     

Materials for the 80's and 90's

The factors governing the application of new materials and manufacturing process are reviewed and the criteria for successful exploitation are described. It is shown that developments should be targetted on specific components but there should preferably be several of these in different industries to reduce the risk and maximise the benefits of success. Composite materials — combinationsof two or more material types are believed to have the best future provided that the necessary production and quality control techniques can be developed.