Band 53, Heft 5

Kurzfassung Laserstrahl-Hybridschweißverbindungen aus S1100QL sind sehr gut für den industriellen Einsatz in zyklisch hochbelasteten Leichtbaukonstruktionen geeignet. Vorteile gegenüber dem MAG-Schweißen ergeben sich u. a. aus kürzeren Prozesszeiten, geringerem Wärmeeintrag und der Reduzierung des Verzuges. Blecheben überschliffene Hybrid-Stumpfnähte erreichen die Schwingfestigkeit des reinigungsgestrahlten Grundwerkstoffs. Poren im Schweißgut sind der begrenzende Faktor. Der Einsatz der Schweißverbindungen ist sinnvoll bei hohen Mittelspannungen und geringen Lastspielzahlen. Hier ergibt sich ein Vorteil des Schleifens gegenüber dem UIT-Verfahren zur Erzeugung von Druckeigenspannungen am Nahtübergang. Auslegungs- und Fertigungsaspekte sowie Prüferfordernisse werden erörtert.

Since the introduction of aseptic surgery by Lister towards the end of the eighteenth century, engineering materials have been implanted into the human body in many forms. Implant surgery has developed to the extent that implants are now used in most branches of surgery and are becoming increasingly more sophisticated. Orthopaedic surgery probably uses more implants than any other branch of medicine. Fracture fixation being one of the oldest and most common applications. This literature review tries to inclusively summarize the recent development in bio-medical materials and its applications in human joint implants up to year 2010.

In this work, the effect of processing temperature of polypropylene (PP) on the viscosity and the melt flow index (MFI) is studied towards the best fabrication of PP/kenaf composites. PP with MFI grade 41 and as density value of 0.95 g/cm 3 is used as a raw material. The compression moulding machine is utilized to produce the moulded samples from PP pallets. The viscosity and the MFI tests have been selected as criteria to determine an optimum processing temperature. As optimum temperature 230°C has been found.

Kurzfassung Die Bedeutung leichter, aber ebenso fester Werkstoffe hat aufgrund des Trends hin zum Leichtbau stark zugenommen. Insbesondere Aluminium-Gusslegierungen zählen zu den Profiteuren dieser Entwicklung. Zeitgleich ist eine erhebliche Zunahme der Anforderungen und Erwartungen an die Werkstoffe, insbesondere bei der Ermüdungsfestigkeit zu beobachten. Die Materialdämpfung ist eine Größe, die beschreibt, inwieweit ein Werkstoff in der Lage ist, elastische Schwingungsenergien umzuwandeln. Der Beitrag gibt eine kurze Einführung in das Phänomen der Materialdämpfung mit ihren Einflussgrößen. Der zur Messung der Materialdämpfung und der Resonanzfrequenz verwendete Versuchsaufbau wird eingehend beschrieben. Anhand von Umlaufbiegeversuchen sowie Zug-Druck-Ermüdungsversuchen an der Legierung AlSi7Mg0,3 soll untersucht werden, ob die Materialdämpfung mit einer fortschreitenden Ermüdungsschädigung verknüpft ist. Die Ergebnisse zeigen, dass eine Änderung der Dämpfung in Abhängigkeit von der Zyklenzahl besteht und dass sich diese Änderung mit der Ermüdungsbelastung korrelieren lässt.

This work aims to evaluate waste marble dust in building industry therefore minimizing the environmental effects of waste dust and maximizing economic benefits with reducing the use of raw material and energy. The marble process industry generates a large amount of wastes during quarrying and sawing processes which pollute and damage the environment. There are many fields in which the marble wastes can be used, one of them is to use them in building industry. In this work, marble dusts provided from 3 different quarries, coming from 3 different places were coded as BN1, BN2 and BN3. After characterizing tests of the dust, they were used in the production of artificial marble tiles using a different amount of resin binder. By the respective physical, optical, chemical, and mechanical tests the maximum quantities that can be added have been determined. The results show that using 80 wt.-% marble dust and 20 wt.-% resin gives the best properties in tiles.

Metallic foams represent materials with low densities as well as good physical, mechanical, thermal, and electrical properties. Since they have pores, metal foams have a set of unusual properties compared with bulk structural materials, i. e. the can offer a unique combination of several properties that can not be obtained in one conventional material at the same time. Metal foams can be produced by different processing technologies and many of them are still under development. The lost foam technique is an alternative foundry process as compared to other conventional techniques. This paper reports about a new approach for the production of open-cell aluminium foam metal by such casting procedure. During the process, an expanded polystyrene cell has been used for pattern making and all critical steps for manufacturing open-cell metal foam by the new technique are described in detail.

Commonly applied in situ procedures with the aim of producing alumina particles or whiskers include the reactions between a metal oxide and aluminum. The metal, reduced with the alumina formation reaction, afterwards generally reacts with Al and transforms into an intermetallic form which will act as a reinforcing member in the composition of the matrix. In this study, by adding CuO powder in ratios of 5, 10 and 15 wt.-% composite billets were produced by the in situ procedure of stir casting. XRD patterns and microstructures of the produced Al-Al 2 O 3 composites were examined by using optical and electron microscopy (SEM). Following the homogenization procedure on the composite material, hot deformation and thermal aging procedures were applied. The changes in the mechanical properties were compared with commercially pure Aluminum.

For the study behind this report, Shell Donax TC 30 oil is added by percentages of 1 and 2 vol.-% to sea water samples which are taken from the beach of Florya near Istanbul in Turkey. Additionally, active and inactive rubber powder has been added by various percentages of 1, 2, and 5 vol.-% to such mixtures. After this, the result of cleaning process efficiency has been investigated after 1, 3, and 5 minutes. For comparison, carbon black has been used in another series of experiments. At the end of the different time periods, the process of cleaning by using rubber powders shows that a cleaning of over 98 % is achieved. During the cleaning process it is observed that oil is absorbed by the rubber powder and that its size becomes larger. The results make evident that rubber powders can be easily used in such new cleaning processes (at least 4 times) after the respective drying.