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2005
Conference Paper
Titel
Alloying and sintering behaviour of selected iron-graphite-master alloy powder mixtures
Abstract
Several master alloys with defined chemical composition, able to generate liquid phases at relatively low temperatures, were identified and produced by gas atomisation. Relevant thermodynamic calculations, including melting ranges for the master alloys, cooling and lever rule diagrams for the PM steels under consideration, were carried out using the ThermoCalc program and databases. The studied materials were prepared by blending the master alloys with a commercially available iron powder and graphite, in predetermined proportions. Liquid phase sintering of the die-pressed powder mixtures was performed at a sintering temperature of 1280ÂșC during 1hr. Interrupted sintering experiments, followed by water quenching from selected temperatures, were performed for studying the alloying mechanisms and the microstructural development of the steels. DSC and Dilatometry were used as an aid for the interpretation of the microstructural observations. Additional experiments, carried out to study liquid formation and the diffusion paths leading to the redistribution of the alloying elements, were performed through the preparation of special powder mixtures.
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