Mechanical properties of Al2O3\Ti composites fabricated by spark plasma sintering

Al2O3\Ti composites presenting a range of metal to ceramic ratios were fabricated using SPS technology and subsequently characterized. A titanium hydride that decomposes in the 600-700 degrees C temperate range was used as the source of Ti. The composite densification process was initiated at 825 degrees C, and reached a maximum densification rate at 1150 degrees C. Microstructural analysis revealed the homogenous distribution of submicron-sized Al2O3 grains and micron-sized Ti grains. Thus, the fine microstructure of the composites provided improvements in hardness, Young's moduli and flexure strengths. The composites displayed lower resistance to fracture than did pure alumina, with cracks largely propagating around the alumina grains, which indicates that the ceramic-metal interface is weak. Finally, the formation of a Ti-Al-O solid solution at the metal/ceramic interface was detected by scanning electron microscopy and X-ray diffraction. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.