Selective laser melting of Al-Zn-Mg-Cu: Heat treatment, microstructure and mechanical properties

An Al-Zn-Mg-Cu alloy with high zinc content was successfully produced by selective laser melting (SLM). A small amount of discontinuous η particles precipitates into the inter-dendritic areas, which is less than in the corresponding cast sample. After T6 heat treatment, almost all η particles dissolve in the Al-matrix. The hardness of the as-synthesized SLM material is 133 ± 6 HV0.05, similar to the homogenized cast sample, and it increases to 219 ± 4 HV0.05 after the T6 heat treatment. This value is higher than for the corresponding T6 cast sample, which indicates that SLM processing leads to a material with improved mechanical behavior.