Automated Multi-Scale Microstructure Heterogeneity Analysis of Selective Electron Beam Melted TiAl6V4 Components

In additive manufacturing (AM) the moving heat source and layer deposition gives rise to each volume of material receiving a complex thermal history. In addition, the machine control systems can vary the heat input as a function of the component geometry and process themes. Together, this can potentially cause both short and long range microstructure heterogeneity, which can potentially impact on the local mechanical properties of AM components. To systematically quantify the heterogeneity typically seen in the lamellar microstructures found in AM titanium parts, a tool has been developed that combine’s automatic high resolution SEM image mapping with batch image analysis, to enable efficient quantification over large areas at the required resolution. This method has been applied to parts produced in Ti6Al4V by selective electron beam melting using an Arcam machine. The method and test cases are described, where both long and short range heterogeneity have been identified in samples and correlated to the build parameters.