Microstructure and properties of nano-TiCp/ GH3536 composite powders prepared by two-step method

Nano-TiCp /GH3536 composite powders were prepared by mechanical alloying (MA ) and thermal plasma spheroidization (TPS ) methods. The flowability , bulk density, particle size distribution,sphericity , and microstructure of the composite powders before and after MA-TPS treatment were studied by Hall flow meter ,Scott ,Scott volumeter, XRD, particle size analyzer, scanning electron microscope , and transmission electron microscope. The results show that the preformed powders obtained by MA-5 h treatment are irregular shape powders with non-uniform adhesion of nano-TiC particles on the surface of the GH3536 substrate. Compared with the original GH3536 powders , the number of equiaxed grains in the preformed powders increases and the crystal grains are refined , but the flowability and bulk density decrease. The nano-TiCp/GH3536 p /GH3536 composite powders obtained by the second TPS treatment are spherical, and the original irregular nano-TiC particles are spheroidized and uniformly distributed inside the GH3536 substrate. After removing the submicron particles with an average particle size of 183. 27 nm, the flowability, bulk density, and sphericity of TPS composite powders are further improved. The TEM images of submicron particles show that the nanoscale GH3536 microspheres are uniformly coated with a layer of TiC, the structure is similar to the core-shell, and spherical TiC particles are found in the powder. The average spherical degree, average particle size, flowability,and bulk density of the nano-TiCp/GH3536 composite powders prepared by the two-step method are 0. 965,33. 65 mu m,17. 1 s/50 g, and ,and 4. 184 g/cm(3), respectively.