Microstructures and Properties for a Superalloy Powder Mixture Processed by Electron Beam Melting

The microstructures and residual hardnesses for solid components of 2-phase TiAl (Ti-48Al-2Nb-2Cr in a/o) and Inconel 625 (Ni-19Cr-9Mo-4Nb in w/o) fabricated by electron beam melting (EBM) were compared with a 10:1 blend of TiAl: alloy 625 pre-alloyed powders producing a complex alloy having the composition 48Ti-24Al-9Ni-8Nb-4.5Cr-4Ni (in w/o). The blended alloy hardness (HV) reached 7.5 GPa in contrast to 1.4 GPa for the Alloy 625 and 4.0 for the 2-phase TiAl alloy. Reticulated mesh samples and stochastic foam samples prepared from the blended alloy by EBM exhibited a relative stiffness versus relative density plotted on a log-log basis consistent with other reference alloys fitted to a straight line with a slope n = 2 for ideal open cellular materials.