Layer thickness dependence of performance in high-power selective laser melting of 1Cr18Ni9Ti stainless steel

High-power selective laser melting (HP SLM) technology has been used to build 1Cr18Ni9Ti samples with 60-150 μm thick powder layers as shown in the above figure. With increasing layer thickness from 60 μm to 150 μm, the primary cellular dendrite spacing first increases from about 0.5 μm to 1.5 μm and then stabilizes around 2.0 μm. The microhardness of the HP SLMed samples shows directional dependent due to the anisotropy of microstructure and grain coarsening in the bonding area. Tensile strengths of the HP SLMed 1Cr18Ni9Ti are much higher than those of wrought 1Cr18Ni9Ti regardless of layer thickness and building direction. Importantly, the powder layer thickness cannot be increased without limit to ensure the comprehensive performance of the HP SLMed samples.