Characterization of iron alloy produced by powder metalurgy

In this study, Fe and Fe-2 Ni samples were produced by powder metallurgy and they were characterized. Fe and Fe-2 Ni powders were milled in 0-120 minutes range. Milled powders were compacted by cold pressing and warm compaction to produce green samples. Produced green samples were sintered under argon atmosphere at 1120oC for 30 minutes. Sintered and non-sintered samples were subjected to 3 point bending tests, hardness and density measurements, and microstructure examinations. As a result of milling, it was seen that the particle size of powders increased by agglomeration. As compared to cold pressing, warm compaction provided a significant increase in the strength and hardness of raw samples. Hardness values of cold pressed samples were in 40-60 HB10 range and they increased to 120-160 HB10 range as a result of warm compaction. Raw strengths of samples increased from 2-30 MPa to 40-180 MPa range. Densitiy values of raw and sintered samples increased by 2%. Strength values of raw and sintered samples decreased as a result of increasing milling time. It was seen that when warm compaction was applied, the decrease of strength values were much less as compared to cold pressed samples. In optical microscope studies it was seen that Ni particles were not completely dissolved in Fe and that dispersion of Ni was better as a result of increased milling time.