Practical Metallography Volume 45 Issue 10

Practical Metallography

Volume 45 Issue 10

Contents
Journal Overview

The Effect of Welding Parameters on the Microstructure and Mechanical Properties of Friction Stir Welded AA 7075

Çinar Yeni May 20, 2013 Page range: 479-494

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Abstract

In this study, aluminum alloy 7075 (AA 7075) has been friction stir welded by using three different rotation speeds and two different welding speeds. The aim is to determine the optimum welding parameters concerning these two variables for AA 7075. Microstructural examination, hardness measurements and room temperature tensile tests have been carried out in order to determine the optimum combination. The results show that higher rotation speeds have yielded higher mechanical properties. Some porosity has been obtained for the lowest rotation speed.

Metallurgical Investigation of Defects in Super Alloy 718 Mill Forms Intended for Aerongine Applications

V. Gopala Krishna, G.D. Janakiram, C.H.V.S. Murty, M. Srinivas, A. Venugopal Reddy May 20, 2013 Page range: 495-504

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Abstract

Super alloy 718 finds extensive utilization, particularly in aero engine industry, due to its excellent strength, low cycle fatigue and creep resistance. The alloy was manufactured using vacuum induction melting followed by vacuum arc remelting techniques. The electrodes, after thermo-mechanical processing to hot rolled square bar and flat forms, were ultrasonically inspected prior to machining of aeroengine compressor blades. During machining, crack-like defects were noticed. Visual / Stereo microscopic examination revealed that the defect was along the length of airfoil and was located at mid airfoil width. The defects were filled with dark gray colored debris. Fractographic examination of the crack facets revealed flaky gray region containing number of cracks and bright region with dimpled rupture features covered with debris. Analysis of the debris indicated the presence of oxygen in addition to the elements present in the material, suggesting that the debris is essentially an oxide. These features were correlated with processing histories and defect morphologies.

Ringversuch Probenpräparation einer gespritzten Multifunktionsschicht auf CFC-Substrat

Philipp Watermeyer, Robert Füllmann, Kurt Baumann, David Beckers, Martina Göbbels, Michael Holztröger, Dieter Koch, Renate Peters, Patrick Voos, Klaus Watermeyer, Wilfried Werner May 20, 2013 Page range: 505-513

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Abstract

Kurzfassung Der Aachener Arbeitskreis möchte hiermit einen aktiven Beitrag zu den präparativen Publikationen leisten und diverse Präparationsvorschläge seines diesjährigen Ringversuchs veröffentlichen. Der Arbeitskreis Metallographie Aachen (AMA) besteht aus einem regionalen Netzwerk metallographisch tätiger Personen. Ein gegenseitiger Erfahrungsaustausch unter anderem bei der Präparation komplexer Werkstoffverbunde steht dabei im Vordergrund. Um die Stärken und Erfahrungen einzelner Mitglieder bezüglich ihrer Präparationsmethoden und ausstattungsbedingten Möglichkeiten näher kennen zu lernen, werden Ringversuche organisiert. Der diesjährige Ringversuch beinhaltete die randscharfe Präparation einer gespritzten Mullitfunktionsschicht auf einem CFC-Substrat.

Arbeitskreis “Ausbildung” im Fachausschuss Materialographie der DGM

Gundula Jeschke May 20, 2013 Page range: 514-516

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About this journal

Practical Metallography is a bilingual (German-English) journal that informs you thoroughly on materialographic preparation, imaging and analysis of microstructures. The journal covers the development and improvement of metallographic methods and equipment, possibilities of optical and electron microscopy, spectroscopy, diffraction techniques, non-destructive testing, metallographic investigations of materials, problems of specimens preparation and evaluation including useful laboratory advice and recipes, failure analysis including damage detection and elimination.
All articles are subject to thorough, independent peer review.
Practical Metallography works closely with Deutsche Gesellschaft für Materialkunde e.V. (DGM)