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Journal of Advanced Ceramics

Article Title

Microstructure and mechanical properties of Zr3Al3C5-based ceramics synthesized by Al–Si melt infiltration

Keywords

Zr3Al3C5, ultra-high-temperature ceramics (UHTCs), twin, carbide, Al–Si alloy

Abstract

In this work, bulk Zr3Al3C5-based ceramics were synthesized by the infiltration of Al–Si melt into zirconium carbide (ZrC) perform. The phase composition, microstructure, and mechanical properties of as-fabricated ceramics were studied. The results demonstrate that Si is more effective to reduce the twin boundary energy of ZrC than Al, and thus promotes the decrease of formation temperature of Zr3Al3C5. With the infiltration temperatures increasing from 1200 to 1500 ℃, the Zr3Al3C5 content increases from 10 to 49 vol%, which is contributed to the increase of flexural strength from 62±9 to 222±10 MPa, and fracture toughness (KIC) from 2.8±0.2 to 4.1±0.3 MPa·m1/2. The decrease of mechanical properties for the samples fabricated at 1600 ℃ is ascribed to the abnormal growth of Zr3Al3C5 grains.

Publisher

Tsinghua University Press

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