Influence of porosity and hBN content on the damping capacity of metal matrix composites

ABSTRACT

Sintered iron samples were produced using different pressing loads, resulting in different residual porosities of approximately 14%, 18%, 22% and 30%. Iron-matrix composites, containing 2.5, 5.0, 7.5 and 10.0 %vol. of dispersed hexagonal boron nitride (hBN) particles, were also produced. The influence of these parameters on the amplitude-dependent damping capacity was assessed using a dynamic-mechanical analyser. The simultaneous effect on mechanical strength was assessed through a tensile test. The microstructure was analysed with optical and electronic microscopy and quantitatively evaluated through a digital image analysis. It was verified that the increase of porosity did not lead to a representative increase in the damping capacity of sintered iron. On the other hand, higher hBN content leads to a higher damping capacity due to the introduction of robust new damping mechanisms. However, hBN reservoirs, which are bigger and more elongated than the pores, are more detrimental to mechanical strength.

KEYWORDS:

• Damping capacity
• amplitude-dependent internal friction
• hidamet
• dynamic-mechanical analysis
• sintered iron
• porosity
• iron-matrix composite
• hexagonal boron nitride

Acknowledgements

Special thanks to the Laboratory of Vibration and Acoustics (LVA - UFSC), to CIMJECT-UFSC and the LCME-UFSC for the technical support.The authors also acknowledge BNDES, Whirlpool/Embraco and CAPES for their financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

Gustavo Adolfo Rodrigues Paz received his M.Sc. in Materials Science and Engineering in 2016 from Federal University of Santa Catarina, Brazil. He is currently pursuing Ph.D. in Materials Science and Engineering from the Federal University of Santa Catarina, Brazil. His main research activity is in the powder metallurgy field with emphasis in the development of innovative tailor-made iron-based composites.

Braulio H. A. Campos is a materials engineer. He has got his degree recently in the Federal University of Santa Catarina, Brazil.

Paulo Henrique Guimarães de Souza is a M.Sc in Materials Science and Engineering. His main research interests are in metallurgy, functional materials and novel manufacturing processes.

Guilherme Oliveira Neves received his Ph.D. in Materials Science and Engineering in 2020 from the Federal University of Santa Catarina, Brazil. His main research activity is devoted to synthesis of carbon nanostructures, powder metallurgy, computation thermodynamics and solid lubrication.

Cristiano Binder received his Ph.D. in Materials Science and Engineering in 2009 from Federal University of Santa Catarina, Brazil. He is currently an assistant professor in the Federal University of Santa Catarina, Brazil. His main research activity is devoted to powder metallurgy, plasma processing and surface engineering.

Aloísio Nelmo Klein received his Ph.D. in Engineering in 1983 from Technische Universität Karlsruhe, Germany. He is currently a full professor in the Federal University of Santa Catarina, Brazil and has been the coordinator of the Materials Laboratory (Labmat/UFSC) since 1984. His main research activity is devoted to powder metallurgy, plasma processing and surface engineering.

ORCID

G.A.R. Paz http://orcid.org/0000-0002-0849-3175

G.O. Neves http://orcid.org/0000-0001-9733-8582

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Ní vel Superior (CAPES); Embraco; Banco Nacional de Desenvolvimento Econômico e Social (BNDES).