Experimental investigation and numerical modelling of dynamic compaction process of pure iron powder with ceramic particles

Experimental investigation and numerical modelling of dynamic loading effect on the density, strength and microstructure of the pure and composite parts fabricated from iron powder has been studied in the present paper. Experimental tests have been performed using drop hammer apparatus. Diametral compression test has been used to evaluate the strength of fabricated parts. Also, numerous micrographs have been provided using scanning electron microscopy to investigate the influence of impact loading on the microstructure of compacts. The obtained results show that with increasing compaction energy, density and strength of pure parts increase in three ranges of low, medium and high pressures with different rates. Also, the obtained results by compaction of iron powder with different ceramic powder contents under equal pressure reveal that adding more than 5 percent of ceramic content, sharply decreases the density of composite parts. Examination of graphs taken from the microstructure of compacts reveals that propagation of compressive stress waves through the powder column, causes plastic deformation of particles and forms mechanical inter-locking on a completely uniform structure. Furthermore, a mathematical expression has been presented using dimensional analysis along with genetic algorithm method to predict the values of density of produced pure parts. In this method, after constructing dimensionless numbers based on dimensional analysis approach, these numbers have been used as the inputs of genetic algorithm modelling method. Comparison of the values predicted by this equation with those obtained by experimental values, shows that the results obtained by this model, agree with experimental results surprisingly.