Thermal conductivity mapping of the Ni-Al system and the beta-NiAl phase in the Ni-Al-Cr system

We use two examples to highlight the power of micron-scale-resolution thermal conductivity mapping on graded compositions created in a diffusion-multiple sample in rapid establishment of composition-phase-property relationships. The Ni-NiAl diffusion couple example clearly shows the effects of solid solutioning, order-disorder transition, and compositional point defects on thermal conductivity. Thermal conductivity mapping of the beta-NiAl phase region of an Ni-Cr-NiAl diffusion triple clearly shows that Cr substitutes for both Ni and Al sites in beta-NiAl without a strong preference, which is also found not to be strongly composition dependent.