Microstructure And Properties Of TiCp/EPS And TiCp/Fe Composites

The deformation and failure zone of the composite materials is mainly concentrated near the agglomerated particles.Therefore,it is of great significance to avoid the agglomerations of ceramic particles in composite materials and realize the uniform distribution of ceramic particles in the matrix,so as to improve the mechanical properties of castings.In this paper,TiC particles are mixed with EPS to form a lost foam model,and TiCp/Fe composite is prepared.The wear resistance,impact toughness and the homogeneity of reinforced particles in the composite materials are studied.The effect of binder concentration on the bonding effect of TiCp/EPS composite is studied by vibration weight loss method.A type of binder is selected with a concentration of 0.2g/ml.In the next,the strength of TiCp/EPS composite is measured by hydraulic universal strength tester.According to the strength test results,the maximum volume fraction of TiC particles in the TiCp/EPS composite is determined to be 8%.The effects of TiC particle size and casting systems(top,bottom or gap)on the microstructure uniformity of TiCp/Fe composites are investigated by means of metallographic microscope,SEM and EDS.The results show that with the decrease of TiC particle size,the particle distribution is more uniform.The standard deviation of the TiCp/Fe composite test block prepared with 1500 mesh TiC particles in slot casting is 1.17with the best uniformity.The effects of TiC particle size on the hardness,wear resistance and impact toughness of TiCp/Fe composite test samples under casting systems(top,bottom or gap)are studied.The results show that the more uniform the particle distribution,the better the mechanical properties of the composite casting.The TiCp/Fe composite backing plate casting prepared with 1500 mesh TiC particles has the best mechanical properties,including hardness of47.1HRC,relative wear resistance of 1.80,and impact toughness of 12.8 J/cm~2.Among all the samples,the composites casting with 1500 mesh TiC particles prepared by the gap casting system show the highest particle distribution uniformity and the best mechanical properties.