Effect of Post-weld Heat Treatment on Microstructure and Mechanical Properties of Laser Beam Welded TiAl-based Alloy

Post-weld heat treatment is carried out on the laser beam welded γ-TiAl-based alloy Ti-48Al-1Cr-1.5Nb-1Mn-0.2Si-0.5B (at. pct). The macro/microstructure and mechanical properties of both as-welded and heat-treated specimens are investigated by radiography, SEM, and tensile tests. Moreover, high energy synchrotron X-ray diffraction is performed to measure the residual stresses and evaluate the microstructure evolution. It is found that the residual stresses are distributed in a three-peak shape in the region of the weld zone and heat-affected zone of the as-welded specimen due to the microstructural transformation and heat softening. The residual stresses are largely relieved after the heat treatment. The heat-treated specimens have a near fully lamellar microstructure and show balanced mechanical properties of strength and ductility. The diffraction shows that the phase transformation from α ₂ to γ takes place under tensile load at 1023 K (750 °C), and the grain size and lamellar spacing are refined in the weld zone. Finally, the fracture mechanisms are found to be controlled by the local stress concentration-induced strain misfit between α ₂ and γ phases in the near γ grains and delamination and debonding in the lamellae. Boride ribbons of 5 μm in the near fully lamellar microstructure are found not to be detrimental to the tensile properties.     

Take care of your belongings today – securing accessibility to complex electronic business processes

Most of today’s business processes are based solely on digital data. Input, output, and intermediate results are pure digital objects. Keeping such data accessible and meaningful but even more importantly keeping the business processes functional is challenging. With regards to complex electronic business processes traditional archiving does not provide satisfactory results. Due to the fast technical life-cycle the time gap between archiving and re-enactment or reuse of a process poses risks and increases the uncertainty on achievable results. We propose a novel strategy bridging this specific time gap. For this we present a scalable and cost-effective infrastructure with associated workflows focusing on a process’ execution context. Most importantly the process’ developers are able to assess the preserved results in a timely manner, and thus, reduce the uncertainty on future re-enactment results.     

Designing sustainable work systems: The need for a systems approach

There is a growing discussion concerning sustainability. While this discussion was at first mainly focused on a society level – and sometimes regarding especially environmental problems, one can now see that this topic is of increasing relevance for companies worldwide and even the social dimension of this three pillar approach is gaining more and more importance. This leads to some questions: Is sustainability already a part of human factors thinking or do we have to further develop our discipline? How can we define sustainable work systems? What are the topics we have to consider? Do we need a new systems ergonomics perspective regarding whole value creation chains and a life-cycle perspective concerning products (and work systems)? How can we deal with potential contradictions about social, ecological, and economic goals?     

LA-ICP MS Characteristic of Geochemical Composition of Veins Rocks from the Central Part of the Khibina Massive in Kola Peninsula,Northern Russia

This paper discusses the vein rocks located in the central part of Khibina Mts.. These rocks are located on the border of two zones： ore and external. In the ore, zone is present titanite-nepheline bodies whilst in the outer zone are massive-syenites ＂khibinites＂. The veins can be divided into： mikrosyenites, melteigites and other rock types （e.g., tinguaites）. The results of LA-ICP MS （laser ablation of inductively coupled plasma mass spectrometry） indicate that these rocks are associated with deep zones which formed as a result of injection of primary magma and contamination of fluids during migration, where there have hydrothermal processes. Rock-forming minerals, their corrosion and accessory minerals indicate these processes, too.     

Spectral reflectance response of Fraxinus mandshurica leaves to above- and belowground competition

The responses of leaf spectral reflectance of Fraxinus mandshurica saplings to above- and belowground competition were studied under field conditions in a temperate forest near the Changbai Mountain Nature Reserve in northeast China. Two sets of four treatments, each inducing different levels of competition, were applied under the shade of the forest canopy and in a clear felling area under full light exposure. The heights of the saplings were measured once a month and leaf reflectance was measured at the same time. At the end of the experiment, all target saplings were excavated, and their biomass and root morphological traits were analysed. All these traits were then compared with the leaf spectral reflectance values and different spectral indices. We found that changes in height and biomass were significantly affected by the treatment and site, and that the differences between the four treatments coincided well with the differences in the spectral indices. The final biomass and all root morphological attributes were significantly affected by the treatment and site. Again, these differences corresponded well with the differences in the spectral indices and the spectral reflectance curves. In conclusion, we found that leaf spectral reflectance was sensitive to competition and showed a close relation with other responses, which makes it a reliable indicator of the response of F. mandshurica to varying competition intensities, especially when competition is very severe.     

An information system architecture for build- and engineer-to-order production of application services

In manufacturing, substantial efficiency gains have been achieved through industrialization. Key concepts of industrialization include standardization, automation, and modularization. Transferring these to IT service production promises increased efficiency. ERP systems apply such concepts and have been an integrating tool for making production for manufacturers more efficient. However, previous research has considered ERP systems for IT service providers either very broadly or only from a business or technical perspective. This article investigates how to apply the ERP system concept comprehensively to a specific type of IT service provider. To this end, application services are prescribed as being composed of three types of configuration models. This helps to achieve a composition of (IT) application services that is comparable to physical parts, and it further supports their management and automated production within an ERP system. An information system architecture with the ERP system at its core is presented. It supports application service production. All relevant service lifecycle phases are considered and a consistent domain model is provided that connects business and technical layer entities. Targeted companies can improve their application service production in terms of quality and efficiency by leveraging this novel automation- and model-based approach.     

Untersuchungen zum Stoffübergang von Mangan aus Fe-Mn-Schmelzen in hoch-FeOn-haltige Schlacken bei permanentem Phasenkontakt

Ermittlung von Stoffübergangskoeffizienten und deren Vergleich mit Schrifttumsangaben. Feststellung von zwei Reaktionsabschnitten nach Aufgabe von flüssiger Frischschlacke auf das ruhende Metallbad in Al₂O₃- und MgO-Tiegeln. Beeinflussung der Stoffübergangsgeschwindigkeit durch Grenzflächenerscheinungen und Vergrößerung der Stoffaustauschfläche durch gleichzeitige Tiegelauflösung.