Design and Characterization of a Novel NiAl–(Cr,Mo) Eutectic Alloy

To enhance the mechanical properties of NiAl–(Cr,Mo) in situ composites for high‐temperature structural use, achieving a regular eutectic microstructure is crucial. A novel alloy with a composition of Ni 30.6 Al 36 Cr 31.4 Mo 2 is developed that exhibits a significantly reduced solidification interval compared to well‐studied alloys such as Ni 33 Al 33 Cr 28 Mo 6 . This advancement results from using the in‐house developed alloy design tool PyMultOpt and Calculation of Phase Diagrams analysis to minimize the solidification interval. The refined alloy demonstrates a theoretical solidification interval of 0 K. These results are verified with differential scanning calorimetry measurements at different heating rates for the new alloy and compared with the established alloy Ni 33 Al 33 Cr 28 Mo 6 . The small solidification interval leads to a uniform eutectic microstructure consisting of a (Cr,Mo) phase embedded in the NiAl matrix without primary NiAl dendrites present. This indicates that deviating from the stoichiometric NiAl composition results in a significantly lower solidification interval and thus in an actual eutectic composition of the NiAl–(Cr,Mo) system.