Analysis of microstructure and defects in 17-4 PH stainless steel sample manufactured by Selective Laser Melting

摘要

The microstructure and defectiveness of a 17-4 PH sample produced by Selective Laser Melting using nitrogen atomized powder have been studied. The analysis has been performed in both longitudinal and transversal sections with regard to the printing direction. A very fine-grained microstructure has been revealed. The X-Ray analysis has shown the occurrence of both martensitic/ferritic α phase and austenitic Y phase. No significant differences in average hardness values have been observed for cross and longitudinal sections. The average hardness value in the bottom cross section has been found equal to 308±13 HV1/15. Some voids associated with inclusions and not fused powder have been observed. EDX analysis has been used to analyse the chemistry of the inclusions. The area fraction of defectiveness does not exceed the 1% and diameter of inclusions is generally lower than 20 μm.