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R. Oro Calderon, E. Bernardo Quejido, M. Campos Gomez, C. Gierl-Mayer, H. Danninger, J.M. Torralba:
"Master Alloys for liquid phase sintering: some key points for the design";
Metal Powder Report (eingeladen), 71 (2016), 3; S. 184 - 192.

The master alloy (MA) concept was brought up in the early 1970s as a means to introduce alloying
elements with high oxygen affinity in low alloy sintered steels. Afterwards, it evolved to become what we
currently understand: a MA as a powder that - admixed in very small amounts - can be used as a vehicle
to efficiently tailor the microstructure and final properties of the steel through alloying effects. One of
the main advantages of the MA approach is the unique opportunity of designing the alloy composition
to enhance sintering though the formation of a liquid phase with tailored characteristics. This work
presents an overview on some critical aspects to consider during the design of a MA composition.
Particular emphasis is devoted to the interactions between MA particles and iron base powders which
divides the design possibilities into two main families: dissolutive (non-infiltrating) and non-dissolutive
(infiltrating) liquids, with significant differences in the final microstructures and dimensional stability
achieved in the sintered parts. Moreover, when advanced alloying systems containing Cr, Mn and Si are
considered, the study of the interaction with the base powder must also include the chemical reactions
occurring during sintering. In this latter case, application of high purity sintering atmospheres might
not be enough to avoid the formation of stable oxides, since the source of oxygen is in most cases the iron
base powder itself.

http://dx.doi.org/10.1016/j.mprp.2016.03.004