SPS-assisted Synthesis of SIC_p reinforced high entropy alloys: reactivity of SIC and effects of pre-mechanical alloying and post-annealing treatment

ABSTRACT

In this work a traditional high entropy alloy (FeCoNiCrAl) was reinforced by uniformly distributed reactive silicon carbide (SiC) particles by a powder metallurgy synthetic route, using as precursors simply mixed powders or mechanically prealloyed ones. The reactive sintering produced a single isomorphic BCC structure. The sample microstructure resulted equiassic, more homogenous in samples based on prealloyed powders. The instability of SiC in the presence of metal precursors resulted in the formation of more stable carbides and silicides, as well as in carbon diffusion in the high entropy alloy matrix and partially unreacted SiC particles. The formation of these newly formed fine precipitates, as well as the presence of residual SiC were useful to increase the hardness of the alloy.

KEYWORDS:

• Spark plasma sintering
• reinforcement
• high entropy alloys
• powder metallurgy
• SIC
• hardness

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Elena Colombini is a postdoctoral research fellow at the Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia. Her research activity is focussed on the synthesis of new high entropy alloys through metal powder technology. Together with her supervisor (Prof. Paolo Veronesi) she also design new microwave applicators for several employments.

Magdalena Lassinantti Gualtieri is a research fellow at the Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia. She is specialized in synthesis and microstructural characterization of inorganic materials. Her most recent research activities involve development of sustainable building materials.

Roberto Rosa is a postdoctoral research fellow at the Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, and adjunct Professor of Chemistry at the Dipartimento di Scienze e Metodi per l'Ingegneria at the same University as well as at the Dipartimento di Economia Scienze e Diritto at the Università degli Studi della Repubblica di San Marino. His research activities are mainly focused on the use of microwave energy in organic and inorganic chemical synthesis, as well as in processing of materials in general.

Fabrizio Tarterini, PhD, head technician of the Metallurgy Laboratory at DIN Departement, Departement of Industrial Engineering, and expert in Spectroscopic Techniques Paolo Veronesi, Professor of Material Science at the Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia. His research activity is mainly focussed on the thermal applications of microwaves. He is also active in the ceramic field, in particular as far as composite materials and refractory materials are concerned. During last decade he has been using commercial electromagnetic modelling software (Concerto 3.5, Comsol Multyphisics) in order to design new microwave applicators for high and low temperature heat treatments and microwave plasmas. Recently, he dedicated intensively to the development of microwaves applications to metals, high entropy alloys and intermetallics. His research activity lead to many collaborations, either National or International, mainly regarding dielectric heating and materials processing.

Mario Zadra was one of the founder of K4Sint, where he has been worked since 2007. He was graduated and received the PhD in Materials Engineering at the University of Trento with a thesis on “Effect of strain rate and sample geometry on the ductility of aluminium alloys”. He is interested in all the technologies about powder metallurgy, particularly press & sint, metal injection moulding, spark plasma sintering and additive manufacturing.

Angelo Casagrande, Professor of Metallurgy at the Department of Industrial Engineering-DIN -Bologna University. His researcher is aimed to the production of innovative metal alloys, their behaviour in exercise, protective coatings and intermetallics, obtained by reactive synthesis and massive damping materials to reduce mechanical vibrations in structural components.

ORCID

E. Colombini http://orcid.org/0000-0002-0268-8027

M. Lassinantti Gualtieri http://orcid.org/0000-0001-7317-2661