Microstructure and mechanical properties of Scalmalloy® produced by selective laser melting in term of long-term applications

This study investigates the microstructure-property relationships of Scalmalloy ® produced by selective laser melting subsequently subjected to natural aging. The aim of this research was to evaluate the suitability of the alloy for long-term applications. A detailed characterization of the material structure and properties was conducted using scanning and transmission electron microscopy, as well as tensile testing. The microstructure revealed a bimodal grain structure typical for additive manufacturing, consisting of a fine grain zone with an average grain size of 1.4 ± 0.7 µm and a coarse grain zone averaging 10.0 ± 5.6 µm. These zones exhibited distinct crystallographic textures, with the fine grain zone dominated by high-angle grain boundaries and the coarse grain zone by low-angle grain boundaries. In addition, nanoscale precipitates coherent with the Al matrix and uniformly distributed stacking faults were identified, contributing significantly to the mechanical performance of the alloy. The SLM-V samples exhibited excellent mechanical properties, including an ultimate tensile strength of 507 ± 4 MPa, a yield strength of 487 ± 3 MPa, and a total elongation of 9.4 ± 0.7%. The results are also discussed in terms of the recognition of coherent nanoprecipitates within the Al matrix and their influence on the resulting mechanical properties.