Theses and Dissertations

Issuing Body

Mississippi State University


Matthew Priddy

Committee Member

Haley Doude

Committee Member

Zackery McClelland

Date of Degree


Original embargo terms

Complete embargo for 2 years

Document Type

Graduate Thesis - Open Access


Mechanical Engineering

Degree Name

Master of Science


James Worth Bagley College of Engineering


Department of Mechanical Engineering


Additive friction stir deposition is characterized by rotating a consumable feedstock rod that induces severe plastic deformation to deposit material additively without raising the material past its melting point. In this way, additive friction stir deposition differs from traditional additive manufacturing, and new developments in this technology require further investigation of build parameters, tooling, and resultant builds to better understand this printing process and its applications. This thesis evaluated the effect of rotational speed on aluminum 6061 builds using mechanical testing and microstructural investigations. Three different build conditions were evaluated at 180 RPM, 240 RPM, and 300 RPM. Mechanical testing methods were used to determine hardness values, ultimate tensile strength, yield strength, elastic modulus, and density. Imaging techniques including optical microscopy, electron backscatter diffraction, energy dispersive x-ray spectroscopy, and x-ray computed tomography were used to evaluate microstructure, grain size, chemical composition, and porosity.


This material is based upon work supported by the U.S. Army Engineer Research and Development Center (ERDC) under contract W912HZ-19-C-0036. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ERDC or the U.S. Government. Distribution Statement A: Approved for public release; distribution unlimited.

Available for download on Tuesday, August 15, 2023