Browsing by Author "Endler, Dirk"

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    FOR3010: High-Temperature Compressive Behavior of Refractory Alumina–Niobium Composite Material
    (Technische Universität Bergakademie Freiberg, 2026-09-23) Günay, Gökhan; Zienert, Tilo; Endler, Dirk; Aneziris, Christos G.; Biermann, Horst; Weidner, Anja
    The development of coarse-grained refractory composites combining refractory ceramics with refractory metals provides new approaches for high-temperature applications. In particular, coarse-grained Nb-Al2O3 composites are widely interested due to their promising functional properties such as of high thermal shock resistance, low shrinkage and good electrical conductivity. In order to identify and release the potential of these materials in advanced applications, their mechanical behavior should be evaluated. This study presents room- and high-temperature compression behavior up to 1500 °C of Nb-Al2O3 refractory composites manufactured via castable and extrusion technology. The influences of production method, particle size, open porosity as well as temperature and strain rate are discussed. For comparison, pure niobium and alumina specimens are used as reference materials. The results indicate that Nb-Al2O3 refractory composites show high ductility at high temperatures. This behavior is also verified with microstructural investigations by scanning electron microscope (SEM).
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    FOR3010: Influence of particle size and fabrication method on mechanical properties of Nb-Al2O3 refractory composites under compressive loads at high temperatures
    (Technische Universität Bergakademie Freiberg, 2026-09-23) Günay, Gökhan; Zienert, Tilo; Endler, Dirk; Aneziris, Christos G.; Biermann, Horst; Weidner, Anja
    The present study explores the properties of both fine- and coarse-grained refractory composites made from niobium and alumina, designed for high performance applications at extreme temperatures, in abrasive environments, and under mechanical stresses. The effects of various production methods, including casting and extrusion, and different alumina particle sizes (fine or coarse) on the mechanical properties under compressive loads are investigated. Compression tests, as well as stress-relaxation and creep tests under compressive loads, are conducted at room temperature and high temperatures up to 1500 °C. The results are analysed concerning initial open porosities and particle sizes. The findings reveal that both particle size and manufacturing method significantly affect the mechanical properties of Nb-Al2O3 refractory composites. Additionally, the choice of production technique substantially influences the microstructure of the composites, leading to noticeable differences in mechanical performance. This research highlights the essential role of optimizing particle size and production methodologies to enhance the operational properties of Nb-Al2O3 refractory composites.