CHARACTERIZATION AND OPTIMIZATION OF SELECTIVE LASER MELTING MATERIALS THROUGH SMALL PUNCH TESTING

摘要

With the heightened complexity of component design that may be achieved through AM comes an equally complex set of distinct material characteristics caused by the manufacturing method. To properly characterize new materials for use with selective laser melting (SLM), extensive material testing and analysis is necessary. Traditional testing techniques, however, are prohibitive due to the time and cost incurred. Miniaturized testing then becomes an attractive option for assessing material properties of SLM materials. The small punch test (SPT) has been developed for such purposes, where material is scarce or costly. Although lacking formal standardization, SPT has been successfully employed with various materials to assess several material properties and verified by traditional testing results. With the accompaniment of numerical simulations for use in the inverse method and determining correlation factors, several methods exist for equating SPT results with traditional stress-strain results. Additionally, the combination of SPT and SLM is relatively unexplored in literature, though studies have shown that SPT is sensitive to the types of structures and unique material characteristics present in SLM components. The present research therefore focuses primarily on the development and evaluation of a mechanical model of the SPT and its sensitivity to changes in material properties. The evolution of the SPT response with dependencies on the changing properties is then likened to the changes in SLM materials to make a case for the suitability of evaluating and optimizing SLM materials using SPT.