Synchrotron Sub‐μ X‐ray Tomography of Kirkendall Porosity in a Diffusion Couple of Nickel‐Base Superalloy and Nickel after Annealing at 1250 °C. Issue 4 (21st January 2021)

• Record Type: Journal Article
• Authors: Epishin, Alexander; Camin, Bettina; Hansen, Lennart; Chyrkin, Anton; Nolze, Gert
• Is Part Of: Advanced engineering materials. Volume 23:Issue 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-21
• Subjects: diffusions -- nickel alloys -- porous materials -- synchrotron radiations -- three-dimensional tomographies; Materials -- Periodicals; 620.11
• DOI: 10.1002/adem.202001220
• Languages: English
• ISSNs: 1438-1656

Abstract

Abstract : Kirkendall porosity that forms during interdiffusion in a diffusion couple of nickel‐base superalloy CMSX‐10 with pure nickel is investigated. The diffusion experiments are conducted at a temperature of 1250 °C, where the strengthening γ′‐phase is partially dissolved. The porosity is studied by X‐ray sub‐μ tomography with a spatial resolution of about 0.35 3 μm 3 at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. It is found that depending on the distance from the interface the Kirkendall pores take different shapes: octahedral, rounded pyramidal, drop shaped, dendritic, pear shaped, and joint shapes. Such a variety of pore morphologies indicates a complex multistage process of porosity nucleation and growth under vacancy supersaturation of different degrees. The experimental findings are interpreted on the basis of the results of diffusion modeling. It is shown that the kinetics of porosity growth is essentially influenced by the dissolution of the γ′‐phase. Abstract : Kirkendall porosity in a diffusion couple of nickel‐base superalloy with pure nickel during interdiffusion at 1250 °C is investigated by synchrotron tomography with a spatial resolution of 0.35 3 μm 3 . It is found that depending on the distance from the interface, the pores take different shapes: octahedral, dendritic, drop shape, and others. The experimental findings are explained by diffusion modeling.