College - Author 1

College of Engineering

Department - Author 1

Materials Engineering Department

Degree Name - Author 1

BS in Manufacturing Engineering

College - Author 2

College of Engineering

Department - Author 2

Materials Engineering Department

Degree - Author 2

BS in Materials Engineering



Primary Advisor

Blair London, College of Engineering, Materials Engineering Department


Certain nickel-based alloys, particularly René 41, characteristically have many low-angle grain boundaries (grain arrangements of less than 15 degrees), present in the microstructure of an in-use component. Frequently, these low-angle grain boundaries are not optically visible after the etching process, leading to the phenomena of discontinuous grain boundaries. There exists a risk for René 41 grain boundary characterization; since one cannot assume that a grain boundary continues beyond a discontinuity, the grain size requirements become difficult to meet. Despite favorable characteristics of René 41, such as the corrosion and oxidation resistance coupled with excellent strength at high temperatures, the risks associated with discontinuous grain boundaries are one reason why the material has been declining in use. If an etchant were to be found that revealed the discontinuous grain boundaries, it would allow properly processed components to pass specification. We researched chemical etchants for the purpose of revealing these grain boundaries of René 41. The etching process was performed on a cross section of a ring rolled René 41 aircraft engine ring which was cut and sectioned into 48 segments. We were able to identify the existence of discontinuous grain boundaries in the samples, and through the existence of annealing twins, prove that low angle grain boundaries were present in the samples.

Available for download on Wednesday, June 04, 2025

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