Mechanical and wear properties of Si3N4 reinforced titanium composites

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