A deeper insight into the design of creep resistant α-Al2O3/YAG fibers: Effects of seeding material and thermal treatment on the structural, microstructural and mechanical properties

Polycrystalline α-alumina / yttrium-aluminum garnet (YAG) fibers were prepared from aqueous solutions of aluminum formoacetate and yttrium acetate, using α-Al 2 O 3 nanoparticles as a seeding material. α-Al 2 O 3 /YAG fiber production was achieved via dry-spinning with polyvinylpyrrolidone as a spinning aid, followed by calcination and sintering of as-spun fibers at various temperatures, dwell times and heating rates. X-ray diffraction (XRD) revealed the formation of transitional Al 2 O 3 and yttrium-aluminum perovskite (YAP) phases between 1000 and 1300°C, with complete conversion to α-Al 2 O 3 / YAG (76 / 24 wt%) achieved at 1500°C. Full densification required temperatures of at least 1400-1500°C keeping a sufficient dwell time (30 min), though higher sintering temperatures promoted grain growth. Average tensile strength and creep factor m of the related fibers were tailored by adjusting thermal treatment parameters. At 1400°C, fibers exhibited higher strength (up to 1149 MPa, m = 0.57), whereas at 1500°C, they demonstrated enhanced creep resistance (up to 906 MPa, m = 0.69).