Masters Theses


"Magnesium alloys have been fast catching up their attention in applications where both lightweight and exceptional strength is desired. But magnesium alloys suffer formability issues which limit their use to cast applications when designing complicated shapes. Friction stir processing (FSP) is technique for, imparting a fine-grained, homogeneous microstructure by which both strength and ductility can be enhanced. The results from the first part of present work showed that AZ31 alloy when employed the use of FSP, yielded significant strength and ductility gains but on the cost of anisotropy. The cause of anisotropy was investigated to be correlated to texture evolution during FSP.

In the second part, the friction stir lap welding of two different magnesium alloys AZ91 to AM30 has been investigated. The study was aimed to investigate the best tool geometry to yield widest range of defect free parameters along with high strength in welded region. The objective of deciding the best tool geometry was achieved by utilizing hardness profiling of welded regions as well as using process maps for various tool designs. The weld strength of defect free runs was evaluated through mechanical tests; lap shear test and tensile test. The effect of post weld treatment on strength properties was also considered"--Abstract, page iv.


Mishra, Rajiv S.

Committee Member(s)

Newkirk, Joseph William
Dharani, Lokeswarappa R.


Materials Science and Engineering

Degree Name

M.S. in Materials Science and Engineering


Missouri University of Science and Technology

Publication Date

Summer 2009

Journal article titles appearing in thesis/dissertation

  • Influence of texture on mechanical behavior of friction stirred processed magnesium alloy
  • Characterization of Friction Stir Lap Welding of AZ91 magnesium alloy to AM30 magnesium alloy


xii, 61 pages

Note about bibliography

Includes bibliographical references.


© 2009 Gaurav Bhargava, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Friction stir welding
Magnesium alloys
Magnesium alloys -- Mechanical properties
Welded joints -- Fatigue
Strength of materials

Thesis Number

T 10243

Print OCLC #


Electronic OCLC #