Document Type

Open Access Thesis

Embargo Period

5-15-2014

Degree Program

Mechanical Engineering

Degree Type

Master of Science in Mechanical Engineering (M.S.M.E.)

Year Degree Awarded

2014

Month Degree Awarded

May

Advisor Name

Robert

Advisor Middle Initial

W.

Advisor Last Name

Hyers

Co-advisor Name

Jonghyun

Co-advisor Last Name

Lee

Abstract

In sub-millimeter sheets of wrought H-X750 Nickel-base superalloy, aluminum-rich coatings are bonded to matrix with a vapor phase aluminization process. If an appropriate amount of aluminum is bonded to matrix with homogenization treatment, the resulting diffusion couple will diffuse into coherent (g/g’) heterogeneous phases creating matrix that is both precipitation and solid solution strengthened.

The diffusional mechanisms for solid solution mass transport involved with the growth and dispersion of bonded aluminum-rich coatings in the aluminization process only differ from the no external mass flow homogenization process with annealing treatment in that the boundary conditions are different. In each case these forces that activate diffusion at the macroscopic level are connected to the activation energies of random walks of atoms on a wide scale at the angstrom level.

An overview of wrought Nickel-base superalloy is presented. Starting with thin sheets the alloy will be aluminized and homogenized. The research from this study will determine the parameters for the movement of the phase boundaries, mass transport, and the time variant concentration fields for both the aluminization and homogenization processes. This is predictable for both single dimension fluxes assuming the interdiffusivities and fluxes at the phase boundaries are known. Because mass-transport is related to the movement of the phase boundaries through density, an investigation into the less dense aluminum-rich coatings and resultant matrix is also included.

Share

COinS