| B4C ceramics are widely used in the fields of tank armor and aerospace due to their low densities?2.52g/cm3?,high hardness?35-45GPa?and melting points?2450??.However,the shortcoming of the low fracture toughness?<2.2 MPa/m2?limits their further developments.TiB2-B4C ceramics,as a new type of ceramics,inherit the excellent properties of matrix B4C,and the fracture toughness is significantly improved.Although TiB2-B4C ceramics exhibit excellent physical properties,there are few research achievements on the dynamic mechanical properties,especially the crushing behaviors under impact loading.Therefore,in order to improve engineering application abilities of TiB2-B4C ceramics as protective armor materials,the dynamic mechanical behaviors of TiB2-B4C ceramics were studied by means of experiments.Firstly,the basic mechanical properties of TiB2-B4C ceramics were tested.The basic physical and mechanical properties of TiB2-B4C ceramics had been mastered,and the results showed that the bending strengths and the fracture toughness of TiB2-B4C ceramics were significantly better than matrix B4C when other properties were basically the same.Subsequently,the SHPB devices were improved and the dynamic compression tests?SHPB?of TiB2-B4C ceramics were carried out at the loading speed ranges from 5-10m/s.Two typical waveforms,"Single Peak"and"Double Peak",were obtained,and it was observed that TiB2-B4C ceramics had two failure morphologies,namely"Broken"and"Crushed".Besides,the compressive strengths of TiB2-B4C ceramics increasing with raising strain rate were obtained.Finally,the crushing behaviors of TiB2-B4C ceramics under impact loading were conducted.It was found that the experimental waveforms could reflect the changing processes of ceramics;and it was pointed out that there was a certain relation between the changes of energies and the destruction of TiB2-B4C ceramics.Moreover,the calculating formulas for quantifying the degrees of the ceramic breakages were presented. |
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