Article ID Journal Published Year Pages File Type
1610449 Journal of Alloys and Compounds 2014 7 Pages PDF
Abstract

•Microstructural characteristics of a minor Y-Ti2SC phase in a Ni-based superalloy.•The interfacial structures between Y phase and MC carbide.•Y phase can solutionize amounts of beneficial elements Hf and Zr during long-term annealing treatment.

The microstructural characteristics of microphase Y-Ti2SC in Ni-based superalloys have been studied by means of analytical transmission electron microscopy (TEM). In the standard heat treated samples, the Y phase always exhibits slab morphology forming either the sandwiched plate in MC or the side-by-side structure with MC. Moreover, the Y phase also maintains an definite crystallographic orientation relationship of [12‾10]Y//[11‾0]MC and (0 0 0 1)Y//(1 1 1)MC with the MC-type carbide. Stacking fault which results from the insertion of two Ti–C layers has been identified in the Y-Ti2SC phase. Combined with high resolution TEM (HRTEM) and first-principles calculations, we also determine the most stable interfacial structure between Y phase and MC carbide. Additionally, we find that Y-Ti2SC phase can solutionize amounts of beneficial elements Hf and Zr from the matrix during long-term annealing process, which leads to its lattice expansion. This solution phenomenon is detrimental for superalloys due to the consumption of the beneficial elements.

Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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