Masters Theses


Romy Francis


"Laser metal deposition (LMD) can form near net shaped components for aerospace applications. Ti-6Al-4V is a widely used aerospace alloy and fabrication of this alloy using LMD is gaining popularity. Improved mechanical properties are always a requirement in aerospace alloys and research is constantly being conducted to improve the properties of components formed from this alloy. Friction Stir Processing (FSP) in the past has been used as a method to change the surface properties of materials through microstructural modifications. The changes in properties can include hardness, corrosion resistance, fatigue strength, etc. The first section of this thesis is based on a similar concept to modify the surface properties of the laser deposited Ti-6Al-4V through FSP. Microstructural changes in the Ti-6Al-4V laser deposits due to FSP and subsequent laser deposition has been presented. The microstructure was characterized by the SEM and optical microscope. Variations in the microhardness inside the nugget region have also been discussed. The second section of the thesis proposes a methodology to create a fully forged, recrystallized structure by integrating the hybrid laser deposition system and FSP. Various FSP parameters investigated in attaining the same have been discussed. The effective nugget region which was left unaffected due to the subsequent single, double and triple layer laser deposition has also been presented"--Abstract,page iv.


Liou, Frank W.
Newkirk, Joseph William

Committee Member(s)

Midha, A. (Ashok)


Materials Science and Engineering

Degree Name

M.S. in Manufacturing Engineering


National Science Foundation (U.S.)
Air Force Research Laboratory (Wright-Patterson Air Force Base, Ohio)
Boeing Company. Phantom Works
Product Innovation and Engineering, LLC
Spartan Light Metal Products
Missouri University of Science and Technology. Intelligent Systems Center
Missouri University of Science and Technology Engineering Program


Supported by the National Science Foundation grant DMI-9871185 and IIP-0637796, the grant from the U.S. Air Force Research Laboratory contract FA8650-04-C-5704.

Research Center/Lab(s)

Intelligent Systems Center


Missouri University of Science and Technology

Publication Date


Journal article titles appearing in thesis/dissertation

  • Microstructural evolution in friction stir processed Ti-6Al-4V laser deposits
  • An approach towards building a friction stir processed structure using the hybrid laser deposition system


x, 54 pages

Note about bibliography

Includes bibliographical references.


© 2009 Romy Francis, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Titanium alloys -- Microstructure
Friction welding
Pulsed laser deposition

Thesis Number

T 10547

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Electronic OCLC #