I certiEy that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.




 Jo h J. Hren, Chairman
 p6rfessor of Materials
 Science and Engineering


 I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.




 R. T. DeHoff/
 Professor of Materials
 Science and Engineering


 I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.


 -9/ .r -

 G.J. Abbaschian
 Professor of Materials
 Science and Engineering

 I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.



 E.D. Verink, Jr.
 Department Chairman and
 Distinguished Service
 Professor of Materials
 Science and Engineering