Author/Authors :
Sabooni, S Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran , Karimzadeh, F Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran , Abbasi, M.H Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran , Enayati, M.H Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran
Abstract :
Mechanical alloying and pressure less sintering in vacuum have been used to produce bulk
nanostructured Ti5Si3 and Ti5Si3-15wt.% Al2O3 nanocomposite. X-Ray Diffraction (XRD), Scanning
Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used to study the
microstructural characteristics of the samples. Indentation method was used to calculate hardness,
elastic modulus and fracture toughness of bulk samples. The results showed that the nanometric grains
were obtained through mechanical alloying and remained in nanometric scale after subsequent
sintering. It was also observed that the in-situ produced Al2O3 through mechanochemical reaction has
amorphous structure which was crystallized during sintering process. Nanohardness, elastic modulus
and fracture toughness of Ti5Si3-15wt.% Al2O3 nanocomposite were calculated as 1660 HV, 238 GPa
and 5.5 MPa.m1/2 ,respectively, that are higher than those of the monolithic Ti5Si3. Toughening
mechanisms based on crack deflection and crack bridging were suggested as responsible factors for
fracture toughness increase of the Ti5Si3/Al2O3 nanocomposite.
Keywords :
Intermetallics matrix composite , Mechanical alloying , Fracture toughness , Nanoindentation , Powder processing
