Practical Metallography Volume 43 Issue 11

Practical Metallography

Volume 43 Issue 11

Contents
Journal Overview

Schichtbildung auf der Oberfläche einer Cu-Legierung mittels FeMn-Pulver durch Anwendung des WIG-Verfahrens und Überprüfung des Verschleißverhaltens dieser Schicht in Verbindung mit den Produktionsparametern

Hüseyin Turhan May 2, 2013 Page range: 541-558

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Abstract

Kurzfassung In dieser Arbeit wurde auf einer speziell legierten Materialfläche aus Cu, Ferromanganpulver durch Anwendung des WIG-Verfahrens aufgebracht. Der Überzug erfolgte unter anderem durch Variation der Pulvermenge und der Stromstärke. Punktuelle Analysen dieser Schichten wurden mit einem Rasterelektronenmikroskop (SEM) und mit Hilfe der energiedispersiven Röntgenmikrobereichsanalyse (EDX) durchgeführt. In Abhängigkeit von der auf der Oberfläche legierten Pulvermenge wurden dabei verschieden erhöhte Härtewerte erhalten, was auf die Bildung intermetallischer Phasen zurückzuführen ist. Die Abrasionsversuche wurden unter trockenen Bedingungen durchgeführt und die Effekte der Produktionsparameter auf das Verschleißverhalten untersucht. Die Herabsetzung des Verschleißwiderstandes konnte auf die Bildung intermetallischer Einlagerungen der Materialien wie Al 2 O 3 und MnS zurückgeführt werden. Die Bildung intermetallischer Phasen, deren Atome mit metallischer Bindung wie Cu 2 FeAl 7 miteinander verbunden sind, erhöhte somit den Verschleißwiderstand.

Oxide-Scale and α-Casing Characterization in Ti6Al4V Alloy Oxidised in Oxygen Gas

M. N. Mungole, M. Surender, S. Bhargava May 2, 2013 Page range: 559-574

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Abstract

Characterization of oxide scale and α-casing in Ti6Al4V titanium alloy oxidized at 1050, 1150, 1250 and 1340 K for 2, 4, 6, 8 and 12 h in a dynamic oxygen gas atmosphere has been analyzed. The oxide scale exhibited a spalling tendency. Its thickness systematically increased with the temperature and the duration of the oxidation. At a later stage the scale exhibited a catastrophic growth due to the increased porosity. The oxygen stabilized α-phase and its volume fraction as well as its hardness decreased with the distance in the metal matrix (α-casing). Estimated oxygen diffusion coefficients based on the hardness profiles across α-casing were 7.0 × 10 −14 , 8.5 × 10 −14 , and 1.2 × 10 −13 , 1.8 × 10 −13 m 2 /s at 1050, 1150, 1250, and 1340 K, respectively. Similarly, the overall activation energy for diffusion of oxygen in the alloy was 105 kJ mol −1 . EDS analysis across α-casing in the internal oxidation zone revealed sharp concentration wells for Ti and Al. Titanium concentration decreased and that of aluminum increased in these wells.

The Effect of the Process Temperature on the Bondability in Transient Liquid Phase (tlp) Diffusion Bonding of AISI 430 Ferritic Stainless Steel with Nodular (Spheroid) Cast Iron Using a Copper Interlayer

Sermin Ozan, Mustafa Taskin, Sedat Kolukisa May 2, 2013 Page range: 575-585

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Abstract

The effect of the process temperature on the bondability in the transient liquid phase (tlp) was studied. The diffusion bonding of AISI 430 with nodular cast iron using a copper interlayer was investigated experimentally under a protective atmosphere at various temperatures and at a defined constant blow pressure which would cause macro deformation. Microstructure examinations were carried out with the help of optical microscopy, SEM and EDS. Hardness values were measured by HV scale under a load of 150 g. At the bond interface, decarburized and dechromised regions were observed on the ductile cast iron side and stainless steel side respectively. Best mechanical and metallurgical properties were observed for the specimen bonded at 1100°C for 20 min. As a function of an elevation of the process temperature, an increase in the amount of graphite atoms that migrated toward the interface and a reduction at the nodular graphite diameters was noticed.

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)