Characterization Of Evaporative Metal Bonding In Superalloys For Use In Gasified Coal Turbine Generators
Date of Award
Master of Science (MS)
The diffusion bonding of Kanthal APMT, CM247LC, and Rene 80 was studied. The objective of the first part of this work was to create diffusion bonded test samples of Kanthal APMT, CM247LC, and Rene 80 using a 25μm thick zinc interlayer at varying times and temperatures. Then, using scanning electron microscopy to determine the profile of the zinc diffusing into the parent materials, the diffusion coefficients of the zinc interlayer into the materials were determined for each of the materials at each bonding time and temperature. The next objective was to create a finite element model of the bonding process to determine the stresses present at the bondface at the bonding temperature. A model of the geometry used to create the diffusion specimens was created in ANSYS Workbench 14.0. The stress distributions of the model at the bondface were compared to other research of similar bonding conditions to validate the model.
The diffusion coefficients of the materials found for the APMT and Rene 80 followed the expected trend of decreasing as the bonding time increased. It was also observed that the approximate amount of zinc at the bond region decreased from the center to the edge of the bond supporting the theory of evaporative metal bonding. In addition, the nickel based alloys, CM247LC and Rene 80, had diffusion coefficients that approached theoretical diffusion coefficients of zinc in pure nickel. The finite element model showed stress distributions that qualitatively agreed with those reported in other studies although there were some discrepancies. However, it was determined that these were a result of the geometry of the jig used to hold the samples in place for bonding.
Braband, Joshua Elliot, "Characterization Of Evaporative Metal Bonding In Superalloys For Use In Gasified Coal Turbine Generators" (2013). Theses and Dissertations. 1403.