Characteristics of Microstructural Formations Occurring in Additively Manufactured Materials

The characteristic features of the structural composition of different materials manufactured by means of Selective Laser Melting of powdered material in a powder bed (AlSiMg alloy, austenitic steel, cobalt alloy, pure iron) were metallographically examined and imaged using light optical and electron microscopy as well as EBSD analysis. To date, there is not much literature available on this topic, a fact which was one of the motivations behind this contribution. The macroscopic similarities and microscopic differences between the materials will be presented as well as the relation between superstructure and microstructure. By way of example, the effect of later heat treatment on three materials in the as-built condition was examined as well. Depending on the material, very different changes in the structure can be observed.