Open AccessDensification and Mechanical Properties of Alumina Ceramics via Two-Step Sintering With Different Holding Times
Author(s) -
Anis Syufina Mohammad Saufi,
S. Ramesh,
K. Y. Sara Lee,
Tao Wu
Publication year - 2021
Publication title -
international journal of engineering materials and manufacture
Language(s) - English
Resource type - Journals
ISSN - 0128-1852
DOI - 10.26776/ijemm.06.04.2021.05
Subject(s) - sintering , materials science , vickers hardness test , fracture toughness , ceramic , relative density , grain size , grain growth , composite material , alumina ceramic , microstructure , metallurgy
The densification and mechanical properties of alumina ceramics were investigated via two-step sintering (TSS) with different holding time. The alumina ceramics were sintered at 1450 °C for 1 min during the first stage, followed by sintering at 1350 °C with different holding times (2-24h). Conventional sintering (CS) was also performed on the alumina ceramics at 1450 °C for 2 h for comparison purpose. It was found that dense alumina with a relative density above 98% could be attained when TSS with a holding time of more than 12 h. The samples exhibited Vickers hardness between 5-8 GPa and fracture toughness of about 6 MPa.m1/2. In contrast, conventional sintered alumina yielded low relative density (85%), large grain size (2 μm), low Vickers hardness (4.23 GPa) and fracture toughness (4.73 MPa.m1/2). This study revealed that TSS is a viable approach in aiding densification, suppressing grain growth, and improving the mechanical properties of alumina ceramics.