Masters Theses

Keywords and Phrases

Friction stir processing (FSP)

Abstract

"Friction stir welding (FSW) was invented as a solid-state joining process for welding materials at temperatures lower than the melting point of the material. Friction stir processing (FSP) was developed as a modification to FSW, and is used to improve mechanical properties locally through micro structural refinement. FSP uses a non-consumable rotating tool with a pin and shoulder inserted into the material to be processed and traversed along the path of interest. As a result of tool action and subsequent material movement, a processed region of refined microstructure is created along the traverse direction. The mechanical properties of the material in the processed region improve as a result of the microstructural refinement.

The advancing technologies and increasing complexities in operating conditions of components necessitate design and development of economical, energy-efficient and high performance materials in various fields. Meeting an overall objective of obtaining reliable properties with the cost constraints is yet a challenge in many materials. This has broadened the scope of employing newer technologies like FSP to improve the properties of existing materials cost effectively. However, a major challenge for using such improved materials after FSP in actual applications demands an effective elimination or reduction in property variations to obtain reliable performance.

The present work investigated the effectiveness of FSP in surpassing such a challenge in sand cast A1 F357 alloy. The extent of improvement and repeatability of mechanical properties of A1 F357 alloy after FSP are discussed. Using a probabilistic approach, fatigue life reliabilities for two different microstructural conditions were analyzed. Uncertainties in life were predicted and demonstrated for large sample populations using Monte-Carlo simulation. Finally, a combinational approach encompassing product design routine and reliability-based design and optimization principles for applying the FSP to actual components is proposed"--Abstract, page iv.

Advisor(s)

Mishra, Rajiv S.

Committee Member(s)

Kohser, Ronald A.
Stone, Robert B.

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Materials Science and Engineering

Publisher

University of Missouri--Rolla

Publication Date

Fall 2007

Journal article titles appearing in thesis/dissertation

  • Analysis of improvement in mechanical properties of friction stir processed sand cast A1 F357 alloy
  • Reliablistic property analysis and prediction of fatigue life in FSPed Al F357 alloy and microstructural influences
  • Developing a reliability-based design optimization model for FSP zone in products through a functional methodology

Pagination

xii, 97 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2007 Abhilash Raveendranathan, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Aluminum alloys -- TestingFriction weldingSand casting

Thesis Number

T 9285

Print OCLC #

243792466

Electronic OCLC #

1088892709

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