Affiliation:
1. Friedrich‐Alexander Universität Erlangen‐Nürnberg Chair of Materials Science and Engineering for Metals Martensstraße 5 91058 Erlangen Germany
2. Friedrich‐Alexander Universität Erlangen‐Nürnberg Institute for General Materials Properties Martensstraße 5 91058 Erlangen Deutschland
Abstract
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 Ni30.6Al36Cr31.4Mo2 is developed that exhibits a significantly reduced solidification interval compared to well‐studied alloys such as Ni33Al33Cr28Mo6. 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 Ni33Al33Cr28Mo6. 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.
Funder
Deutsche Forschungsgemeinschaft