Practical Metallography Volume 48 Issue 8

Practical Metallography

Volume 48 Issue 8

Contents
Journal Overview

Charakterisierung der Dispersität der Mikrostruktur von Wolframschmelzcarbiden

Alexander Böbe, Mario Böbe, Irmhild Martinek, Andrea Hübner May 8, 2013

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Abstract

Kurzfassung Zur quantitativen Abstufung der Gefügedispersität („Fiedrigkeit“) von blockigen Wolframschmelzcarbiden (WSC) wurde ein Linienschnittverfahren an lichtmikroskopischen Hellfeld-Aufnahmen reliefpolierter Carbidquerschnitte angewendet. Aufgrund des Formzusammenhanges im regellos orientierten Phasengemisch des WSC diente die aus je 15 Carbidorientierungen bestimmte, mittlere Schnittsegmentlänge der δ-WC Phasen zur Quantifizierung der Gefügedispersität. Eine Charakterisierung der Gefügequalität blockiger WSC-Pulver wird durch eine Auswertung von je 120 WSC-Teilchen ermöglicht. Die bislang verwendete, stark subjektive Methode des visuellen Vergleiches, kann durch die vorgestellte computergestützte Bewertung und Klassierung der „Fiedrigkeit“ von WSC ersetzt werden, um durch eine präzisere Carbidpulvercharakterisierung bereits von vornherein die Beschichtungsqualität besser vorhersagen zu können.

Microstructural Changes during Vacuum Carburizing of Steels

Mihael Bruncko, Ivan Anzel, Albert C. Kneissl May 8, 2013

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Abstract

Vacuum carburizing is a modern, very efficient and environmentally friendly process for case hardening of steels. Nowadays the technology has replaced atmosphere carburizing in many cases due to better repeatability and uniformity of heat treated samples. The process of vacuum carburizing is performed under oxygen free hydrocarbon gas atmosphere (usually pure acetylene) at partial pressure lower than 20mbar and in conditions which are far from thermodynamic equilibrium. The process consists of the cycles of active (saturation) and passive (diffusion) stages. Desired case depth and corresponding target concentration profile of carbon can be supervised by controlling the duration of these two stages.

A Mechanical Method for Preparing TEM Samples from Brittle Films on Compliant Substrates

A.A. Taylor, M.J. Cordill, G. Moser, G. Dehm May 8, 2013

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Abstract

Preparing transmission electron microscopy (TEM) samples from thin films is technically challenging and traditional preparation routes can sometimes introduce unacceptable artefacts or even prove impossible. A novel method of preparing plan view TEM samples from thin films by a purely mechanical method is assessed. Two examples of films prepared by this route are briefly presented, a Cr film on PET and an amorphous Al x O y film on Cu. The application of this method allows for TEM analysis of the Cr film without the problems associated with a polymer such as PET disintegrating under the electron beam. For the Al x O y films it is demonstrated that this purely mechanical preparation prevents crystallisation of the film resulting from conventional ion milling preparation routes. The technique also allows for an upper bound of thickness approximation for these films.

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)