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Publications in Scientific Journals:

R. de Oro Calderon, E. Bernardo Quejido, M. Campos Gomez, C. Gierl-Mayer, H. Danninger, J.M. Torralba:
"Liquid Phases Tailored for Introducing Oxidation-Sensitive Elements through the Master Alloy Route";
Journal of the Japan Society of Powder and Powder Metallurgy (invited), 63 (2016), 4; 172 - 184.



English abstract:
Introducing alloying elements through Master Alloy (MA) additions provides the unique opportunity of
designing their composition to enhance sintering by forming a liquid phase. However, working with liquid phases
poses important challenges like maintaining a proper dimensional control and minimizing the effect of secondary
porosity on the final performance of the steel.
The critical parameters for designing low melting point compositions are analyzed in this work by combining
the use of thermodynamic software tools, wetting angle/infiltration experiments, and advanced thermal analysis
techniques. Due to their low ability to dissolve iron, Cu-based liquids present remarkable infiltration properties
that provide homogeneous distribution of the alloying elements. Dissolutive liquids, on the other hand, tend to
render more heterogeneous microstructures, rapidly solidifying in contact with the matrix. As a consequence of
their lower infiltration capacity, dimensional changes upon liquid formation are significantly lowered. When using
master alloys with high content in oxidation-sensitive alloying elements, the differences in oxygen affinity cause
an oxygen transfer from the surface of the iron base particles to the surface of the master alloys. The change in the
surface chemistry modifies the wetting capability of the liquid, and the dimensional stability becomes increasingly
sensitive to the processing atmosphere.

Keywords:
master alloys, liquid phase sintering, oxygen-sensitive alloying elements, dimensional stability, wetting/infiltration


"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)
http://dx.doi.org/10.2497/jjspm.63.172


Created from the Publication Database of the Vienna University of Technology.