Mechanical and optical properties of transparent alumina obtained by rapid vacuum sintering

Transparent polycrystalline alumina with high bending strength and transmission properties has been fabricated using rapid vacuum sintering approach at low temperature. The microstructure, mechanical and optical properties of alumina has been investigated by varying the MgO doping concentration and sintering parameters. Notably, 0.1 wt% MgO-doped alumina with fully density and average grain size of ~11 µm was obtained by sintering at 1670 °C for 5 min, exhibiting the real in-line transmission of 36.37-65.36% at a wavelength of 1068 nm, microhardness of 18.44-25.29 GPa and fracture toughness of 1.61-2.34 MPa m1/2 when the bending strength ranged from 450 to 611 MPa.