Production of Fe-TiB2composite using liquidphase sintering

Abstract: This thesis work focus on evaluating the metallurgical bonding between the TiB2 andiron grains in the Fe-TiB2 composite. The starting materials were commercial materialsin form of Ferro-boron and Ferro-titanium that together with pure TiB2 powder formeda material with the composition seen below:FeB + FeTi + TiB2  52.3TiB2 + 45.7Fe + 2TiDuring sintering an iron liquid phase is formed where the boron from the FeB diffuse tothe titanium in FeTi which enables the formation of TiB2. The temperature used in theliquid phase sintering was chosen just above the three phase region, Fe-TiB2-liquid inthe phase diagram, to get an adequate densification of the samples. However, thetemperature could not be too high because of the internal stress and deformation thesamples would have been exposed to.After sintering the material properties and microstructure were examined throughPalmqvist indentations, Fargo and Transverse-Rupture-Strength tests and SEM studiesincluding EBSD.Through these tests the hardness was measured to 1323 HV and the microstructureconsidered to be fine with well distributed phases. The EBSD also showed that thebrittle Fe2B phase is present close to the TiB2 grains and that the porosity givesunreliable results for the Fargo and TRS-tests. The composite was impregnated withcopper to show that it may be possible to achieve wetting of the TiB2 phase by castingand to perform new tests on the material with less porosity.