A viable strategy for pore evolutional structures and microhardness in cold sprayed additive manufactured SiC/Al composites using TEM and x-ray computed tomography analysis

Abstract In this present work, the internal structure and the 3D morphology of pore structure changes and the effect of SiC fractions on pore structures and micro-hardness with as-sprayed and heat-treated specimens were characterized. The grain structure evolution and the effect of post-heat treatments on pore structures and microhardness were investigated on samples obtained by cold spraying and heat treating deposits on a 6061-T6 hollow cylindrical substrate. Heat treatments were done at various temperatures beyond a homologous temperature of 0.45 T/T m for 8 h. Result showed that the reduction in porosities was attributed to the healing of the interconnectivities of the pores by coarsening of the pure Al grains. XCT technique was a viable method for studying pore evolutional structures. Furthermore, pore evolutional changes were triggered by simultaneous diffusivity interactions of the pores and incremental of the retained SiC fractions. Increment in SiC fractions and heat treatments had significant effect on the sphericity of the pores. The mean sphericity values changed from 0.41–0.62 signifying the pore structure changes with the annealed temperature. The mean equivalent pore diameter for annealed sample at 200 °C was 5.04 µ m with a maximum pore diameter 63.46 µ m, registering a 30% reduction in porosity. The agglomerated size decreased with increased in annealed temperature, signifying that application of heat-treatment helps in deagglomeration of the SiC clusters. The as-sprayed and annealed deposits had an appreciable microhardness results.