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Study of quarternary Ni-base alloys
Picha, R. ; Buršík, Jiří ; Brož, P.
Phase structure of Ni-Al-Cr-Ti and Ni-Al-Cr-Ta alloys was studied at 1000 and 1100C by means of analytical electron microscopy.The coexistence of phases, their compositions and phase ratios in studied alloys showed good agreement with calculations.
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Simulated element redistributions in Ni-based superalloys weldments
Brož, P. ; Buršík, Jiří ; Sopoušek, J. ; Picha, R.
The diffusion and phase precipitation processes in welded joints of pure Al-Cr-Ni system and low alloyed Al-Cr-Ni-X systems (where X means Co, W, or Ti) were simulated using CALPHAD method and DICTRA software. The equilibrium calculations allowed to predict phase diagram cross-sections for the Al-Cr-Ni-X systems. The performed simulations based on local equilibrium condition in diffusion couple enabled to describe the phase transformation process and obtain redistribution of alloying species, activity profiles, and other time-distance dependences for other relevant values in diffusion-affected zone of the Al-Cr-Ni / Al-Cr-Ni-X weldments.
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TEM study of the P phase in model Ni-based alloys
Buršík, Jiří
A microstructure of Ni-Al-Cr-Mo alloys was studied by means of analytical and high resolution TEM. The changes in grain boundary regions during annealing at 873 K include the growth of ordered domains and the precipitation of topologically close packed P phase, which typically exists in a narrow compositional range in Ni-Cr-Mo system.
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