Abstract
The use of low melting point master alloy (MA) powders contributes beneficially to sintering by increasing the distribution rate of alloying elements, enhancing homogenisation and sometimes also promoting densification. However, working with liquid phases poses important challenges like maintaining a proper dimensional control and minimising the effect of secondary porosity on the final performance of the steel. In this work, three different MA systems are compared: a low dissolutive Cu-based MA, and two systems with a higher degree of iron dissolution but different content in oxidation-sensitive elements. The combination of wetting experiments, step sintering tests and dilatometry studies show how the evolution of the microstructure, dimensional stability and overall densification are strongly affected by the characteristics of the liquid MA and in particular by its ability to dissolve the iron base particles, and by the amount of oxidation-sensitive elements present in the composition of the MA powder.
ORCID
Raquel De Oro Calderón http://orcid.org/0000-0001-7341-6267
Elena Bernardo http://orcid.org/0000-0002-7305-6545
Mónica Campos http://orcid.org/0000-0002-8360-9561
Christian Gierl-Mayer http://orcid.org/0000-0001-8944-3534
Acknowledgements
The financial and logistic support given by Höganäs AB Sweden as well as fruitful discussions with all the members of the project is gratefully acknowledged. The authors also wish to thank Dr Capdevila, for his help during dilatometry study. The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013/ under REA grant agreement n° 625556.