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 1100oC 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.