Effect of Ti Doping on the Mechanical Properties of B4C Composite Ceramics

The (100-x)B4C-xTi (wt%) (x=0 similar to 40) ceramics were prepared by hot press sintering at 1680 degrees C, and the effect of Ti doping (x=0 similar to 40) on the microstructure and the mechanical properties of B4C ceramic was investigated. The results show that Ti promotes the sintering of B4C ceramic; its relative density increases firstly, and then it tends to be stable. The relative density of the sample is 99.5%, when Ti doping amount gets up to 40 wt%. The XRD results show that in addition to the B4C and unreacted Ti, there are TiB2 and TiC phase, and with the increase of Ti content, the diffraction peaks of those two phase gradually increase. With increase of Ti content, the bending strength, hardness and fracture toughness of samples increase. When the doping amount is 40 wt%, they reach (481 +/- 24) MPa, (8280 +/- 410) MPa, (18.55 +/- 0.9) MPa.mm(1/2), respectively. The reason is that Ti interface reaction with B4C generates TiC and TiB2 phase transition layer in the interface, which connects the B4C substrate and Ti, and plays an important role in bridging toughening; thus mechanical performance of the material is improved.