Structure and phase composition of metal pulverized powders

Metallographic method, measurement of microhardness and colour film etching were used to investigate the structure and the phase composition of metallic powders (Ni, Fe, Cr, FeMn, Kh18N9 and others). The powders were obtained by atomizing and were composed of various sizes of fractions (fine, with particles up to 40 microns; coarse, with particles in excess of 40 microns). An evaluation is given of the effect of annealing upon the microhardness of powder particles. It was shown that the structure and the phase composition of powders depend on their rate of cooling. Metallic powders of the same chemical composition, but of different sizes have different microstructures. An increase in size of particles results in lower hardness. Annealing of powders lowers microhardness throughout the cross sections of particles