Alloy mixtures with varying composition of two Co-based hardfacing alloys and IN738 Ni-based super alloy were examined using differential scanning calorimetry. The microstructure of the resulting specimens was then analyzed using optical and scanning electron microscopy and energy dispersive spectroscopy. The microstructural evolution between each hardfacing alloy and the IN738 substrate was documented and the formation of topologically close-packed and/or additional carbide phases was noted. Microstructures that are undesirable for high temperature and stress applications were produced in specimens with a higher degree of mixing (from 25 to 75 wt.% of hardfacing alloy in IN738). The two hardfacing alloys produced markedly different microstructures in the alloy mixtures due to differences in elemental composition. A hardfacing process that minimizes the degree of deposit-substrate mixing will be beneficial to the performance of the coating.