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A new class of martensitic stainless steel, namely 06Cr15Ni4CuMo, with applications in marine engineering, was processed by using selective laser melting (SLM). A body-centered cubic martensitic microstructure was observed, and the microstructure was compared with wrought 410 martensitic stainless steel. The SLM-processed sample showed a hardness of 465 ± 10 HV0.5, which was nearly 115 HV0.5 less than the wrought counterpart. Similarly, the SLM-processed sample showed improved YS and UTS, compared with the wrought sample. However, reduced ductility was observed in the SLM-processed sample due to the presence of high dislocation density in these samples. In addition, 71% volume high-angle grain boundaries were observed, corroborating the high strength of the material. The corrosion behavior was investigated in seawater, and the corrosion resistance was found to be 0.025 mmpy for the SLM-processed 06Cr15Ni4CuMo steel and 0.030 mmpy for wrought 410 alloys, showing better corrosion resistance in the SLM-processed material.

Selective laser melting (SLM) is one of the additive manufacturing technologies that allows for the production of parts with complex shapes from either powder feedstock or from wires. Aluminum alloys have a great potential for use in SLM especially in automotive and aerospace fields. This paper studies the influence of starting powder characteristics on the processability of SLM fabricated AlSi12 alloy. Three different batches of gas atomized powders from different manufacturers were processed by SLM. The powders differ in particle size and its distribution, morphology and chemical composition. Cubic specimens (10 mm × 10 mm × 10 mm) were fabricated by SLM from the three different powder batches using optimized process parameters. The fabrication conditions were kept similar for the three powder batches. The influence of powder characteristics on porosity and microstructure of the obtained specimens were studied in detail. The SLM samples produced from the three different powder batches do not show any significant variations in their structural aspects. However, the microstructural aspects differ and the amount of porosity in these three specimens vary significantly. It shows that both the flowability of the powder and the apparent density have an influential role on the processability of AlSi12 SLM samples.