Title: Microstructure and mechanical properties of ZrO₂–reinforced MoSi₂ matrix composites

Authors: Beata Ballokova, Pavol Hvizdos, Michal Besterci, Jozef Ivan, Markus Zumdick, Alexander Bohm, Thomas Weissgarber, Bernd Kieback

Addresses: Slovak Academy of Sciences, Institute of Materials Research, Kosice, Slovak Republic. ' Slovak Academy of Sciences, Institute of Materials Research, Kosice, Slovak Republic. ' Slovak Academy of Sciences, Institute of Materials Research, Kosice, Slovak Republic. ' Slovak Academy of Sciences, Institute of Materials and Machine Mechanics, Bratislava, Slovak Republic. ' Fraunhofer Institute for Applied Materials Research, Dresden, Germany. ' Fraunhofer Institute for Applied Materials Research, Dresden, Germany. ' Fraunhofer Institute for Applied Materials Research, Dresden, Germany. ' Fraunhofer Institute for Applied Materials Research, Dresden, Germany

Abstract: The purpose of the present investigation was to explore microstructure and mechanical properties of two types of composite materials with different amounts of secondary phase (10% and 15% ZrO₂), and their comparison with monolithic MoSi₂. Following metallographic analyses, the identification of phases and residual pores in microstructure was realised. The main criteria for assessment of mechanical properties were hardness, mechanical strength, and fracture toughness determined by two different methods. The results showed that materials with added ZrO₂ particles had better mechanical properties compared to the monolithic one and these properties improved with increase of the ZrO₂ content. Comparison of the two methods of fracture toughness measurement indicates better sensitivity and reliability of the IS method which is less influenced by human factor. The results of EDX analysis showed that the microstructures of the toughened materials contain monolithic MoSi₂ phase, Mo₅Si₃ phase and secondary ZrO₂ phase.

Keywords: composite materials; fracture toughness; mechanical properties; microstructure; EDS analyses; matrix composites.

DOI: 10.1504/IJMPT.2005.006461

International Journal of Materials and Product Technology, 2005 Vol.22 No.4, pp.322 - 327

Published online: 10 Mar 2005 *

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