Interdiffusion at the interface between a Co-36.5Ni-17.5Cr-8Al-0.5Y, MCrAlY coating and the underlying IN738 superalloy was studied in a large matrix of specimens isothermally heat treated for up to 12,000 hours at temperatures 875°C, 925°C or 950°C. Microstructural investigations and calculated phase fraction diagrams show that a precipitate free zone forms between the coating and superalloy and grows with time. Measured composition profiles across the interface were compared with modelled results obtained using the finite difference software DICTRA. The simulated results were able to qualitatively predict the phase-transformations occurring at the interface. The microstructural studies showed that a layer of continuous γ´ was formed on the superalloy side of the interface. This was found in the simulated results as a very high fraction of γ´.
|Title of host publication||EPRI International Conference on Advances in Condition and Remaining Life : Assessment for Fossil Power Plants 2006|
|Publication status||Published - 2006|
|Event||EPRI International Conference on Advances in Condition and Remaining Life : Assessment for Fossil Power Plants 2006 - Louisville, Kentucky, USA|
Duration: 1 Jan 2006 → …
|Conference||EPRI International Conference on Advances in Condition and Remaining Life : Assessment for Fossil Power Plants 2006|
|City||Louisville, Kentucky, USA|
|Period||01/01/2006 → …|