Degradation of Synthesized Material Obtained Using Recycled Powder in SLF Process: Part 1. Porosity and Short-Term Strength at Normal Temperatures

A special type of sample is developed to model modes of exposing surface elements having a constant perimeter and permanent surface area over the entire height to ensure identical conditions to cross-contaminate the construction zone in SLF process. Three consecutive runs carried out according to the method developed confirm that, for high filling density of the construction platform, cross-contamination hardly affects the porosity of the metal synthesized during the first run. When the circulating powder is used, the porosity of the samples grows by a factor of 6 in the second run. After the first run, the average oxygen content in the recycled powder increases by an average of 20–30 rel %; the following two runs result in almost threefold increase in the oxygen content. There is no explicit dependence established between contamination by oxidized jetting and location of samples on the construction platform. The short-term strength tests carried out at a room temperature show high homogeneity of the average plasticity in the first run under a gradual increase in spread and a decrease in plasticity in the two subsequent runs.