TITLE:
Strengthening of Alumina-Based Ceramics with Titanium Nanoparticles
AUTHORS:
Sergio J. Esparza-Vázquez, Enrique Rocha-Rangel, José A. Rodríguez-García, Constantin A. Hernández-Bocanegra
KEYWORDS:
Al2O3, Strengthened, Ti Nanoparticles, Fracture Toughness
JOURNAL NAME:
Materials Sciences and Applications,
Vol.5 No.7,
May
29,
2014
ABSTRACT:
In this
study ceramic materials with a matrix of Al2O3 strengthened with different amounts of Ti nanoparticles (0.0 wt%, 0.5 wt%, 1.0 wt%,
2.0 wt% and 3.0 wt%) were generated. High energy milling was used to mix the
materials in a planetary mill type, in which powder particles were obtained
with sizes of ~300 nm. These powders were uniaxially compacted in cylindrical
samples using 350 MPa pressure. These samples were sintered at 1500°C for 1, 2
and 3 h and at 1400°C, 1500°C and 1600°C during 2 h. Microstructure
observations were made with optical microscopy and scanning electron
microscopy. Dense composites were identified with a homogeneous distribution of
fine particles. Concerning the measurement results of fracture toughness, which
were estimated by the indentation fracture method, it was shown that the
composites made by mean procedure present higher values than the average of the
monolithic alumina, up to 200%. Photographic evidence of arrest of crack growth
by titanium particles was obtained, demonstrating that the reinforcement
mechanism of these materials is due to the deflection of cracks owing to metallic
bridges formed by the titanium used as alumina strengthener.