Characterization of TiB2 reinforced iron based matrix composites produced by powder metalurgy

In this study, production by powder metallurgy and characterisation of TiB2 particulate reinforced iron based matrix composites were investigated. %3, 6,5 ve 10 weight % TiB2 particles were mixed with iron powder having particle size of <10 microns. Green samples which were obtained by cold pressing the powder mixtures at 550 MPa pressure, were pressureless sintered at 1000 oC ve 1120 oC temperatures under argon atmosphere. In addition, samples were produced by adding titanium to these compositions at amounts half that of TiB2 particles. It was aimed to investigate the effects of adding TiB2, Ti and TiB2+Ti into iron matrix on the properties of the composites. After metallographis sample preparation processes, the produced composite parts were subjected microstructural examination by optical microscope and scanning electron microscope (SEM). In order to investigate the mechanical prpoerties of the composites 3-point bending tests and hardness tests according to Brinell 10 scale were conducted. The wear rates of the composites were determined by conducting wear tests on oscillating tribometer with a 6 mm diameter alümina ball under 12 N load. It was seen in microstructural examinations that the TiB2 reinforcement particles were distributed homogenously in iron matrix. According to the energy dispersive x-ray spectrometer spot analyses (EDS) performed during the SEM examinations, it was thought that iron boride phase was present around the TiB2 particles. A considerable increase in the hardness values were obtained by adding titanium diboride reinforcement into the iron matrix. While the hardness values of the unreinforced matrix was about 60 HB10, hardness values increased to over 100 HB10 by adding TiB2 reinforcement. Some more increase in hardness was seen by adding Ti into TiB2 reinforced composites. A decrease in bending strength and % strain values were observed by the increase in the TiB2 and Ti amounts. According to the results of the wear tests, a significant decrease in the wear rates took place with the increase in the TiB2 amount. The wear rate of the composite that contained 10 % TiB2 was found as 1/8 of the wear rate of unreinfored matrix.