Mechanical and wear properties of Si3N4 reinforced titanium composites

Abstract

In the present study, Si₃N₄ reinforced titanium composites were produced by powder metallurgy method.  The effect of various percentages of Si₃N₄ (0-9 wt.%) on the microstructure, density, hardness and compressive strength of titanium (Ti) composites have been investigated. After sintering at 1100^oC for 120 min., the mechanical properties were significantly developed up to 3 wt.% Si₃N₄. The highest hardness and the greatest compressive strength were obtained for 3 wt.% Si₃N₄ reinforced composites (698.5 HV and 1093 MPa) when compared to pure titanium (414.2 HV and 826 MPa). Si₃N₄ addition developed the wear properties of composites when compared pure titanium. The lowest wear rate (1.36x10^-5, 2.75x10^-5 and 5.15x10^-5 mm³/Nm for 10 N, 20 N and 30 N) were obtained for 3 wt.% Si₃N₄ reinforced titanium composite. The scanning electron image, elemental mapping and line analyses confirm the uniform distribution of Si₃N₄ powder in Ti matrix. Above this ratio, the properties of composites were deteriorated due to agglomeration tendency of Si₃N₄ powder. There were no in-situ formed second phases of composite structure from the X-ray diffraction analyses.