Microstructure dependent physical and mechanical properties of spark plasma sintered ZrB2-MoSi2–SiCw composites. (February 2019)

• Record Type: Journal Article
• Authors: Paul, Tanay Rudra; Mondal, Manas Kumar; Mallik, Manab
• Is Part Of: International journal of refractory metals & hard materials. Volume 79(2019)
• Page Start: 131
• Page End: 137
• Publication Date: 2019-02
• Subjects: Borides -- Spark plasma sintering -- Electrical conductivity -- Whiskers -- Toughness; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2018.11.017
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: A comparative evaluation has been carried out off the physical and mechanical properties of ZrB2 –20 vol% MoSi2 composites reinforced with 5, 10 and 20 vol% SiC whiskers (SiCw ). The abovementioned hybrid composites have been densified by spark plasma sintering (SPS) at 1600 °C for 10 min. The present study focuses on the effect of the quantity of SiCw on the densification, electrical conductivity, hardness, and fracture toughness ZrB2 –MoSi2 –SiCw composites in detail. Microstructural characterization suggests that SiCw restricts the grain growth of ZrB2 during densification. The electrical conductivities of the ZrB2 –MoSi2 –SiCw composites have been found to vary in the range ~2.4–3.5 × 10 6 S/m, and it reduce with increasing SiCw content. Results exhibit that the indentation fracture toughness of ZrB2 –20 vol% MoSi2 improves ~70%, ~112% and ~130% with an addition of 5, 10 and 20 vol% SiCw, respectively. An increase in SiCw content leads to more amount of crack deflection and crack arrest that successively improves the fracture toughness of the composites. Highlights: Spark plasma sintering successfully densified the ZrB2 –MoSi2 –SiCw composites with varying amount of SiCw With the increase in SiCw resulted in enhancement in fracture toughness of ZrB2 –MoSi2 –SiCw composites. The fracture toughness of ZrB2 –20 vol% MoSi2 improves by about ~130% with the addition of 20 vol% SiCw . Microstructure suggests toughening mechanism mainly controlled by crack deflection and interfacial debonding.