Characterization of TiC/AA7075 composites produced by powder metallurgy

In this study, AA7075 metal powder with an average particle size of 46.3 μm and TiC reinforcement particles with an average particle size of 5.2 μm were used. Composite powders were prepared adding three different ratios (%5, %10 and %20) TiC reinforcement particles into metal matrix of AA7075 by mechanical alloying process. These composite powders were treated in a planetary type mechanical alloying device at varying times (up to 20 hour). Afterwards, the obtained powders were sintered to produce composite materials at 435 ° C under a pressure of 350 MPa for 30 minutes by hot pressing method. The physical, chemical and mechanical properties of powders produced by mechanical alloying and composite samples were determined with scanning electron microscopy (SEM), X-ray diffraction (XRD), tensile, hardness and density tests. After 2 hours of mechanical alloying, SEM analysis of all groups showed that TiC reinforcement was homogeneously dispersed in AA7075 matrix, average powder size increased due to flake structure formation, and after increasing grinding times, average powder size began to decrease with breaking of flake structure. Experimental results revealed that the tensile strength of composites was increased up to 2 hours and then decreased. Also, the highest tensile strength was obtained for the sample with %20 TiC reinforcement which was mechanically alloyed for 2h. The highest hardness value was obtained by increasing TiC reinforcement and deformation hardening.