Appeal No. 2000-0178
Application 08/686,630
and further that this reference instead describes “an annealed,
hot-isostatically pressed, hot-formed and heat-treated casting,
from which the turbine blade according to the invention is
produced by material-removing machining” (col. 1, line 67-col. 2,
line 2).
To account for the above difference between appellants’
claimed subject matter and Nazmy, the examiner has urged that the
American Machinist article teaches using a laser shock peening
method of hardening a metal by imparting residual compressive
stresses in order to provide superior fatigue life to a metal
part and specifically suggests the application of that method to
parts formed of titanium or titanium alloys. From these
teachings, the examiner concludes that it would have been obvious
to one of ordinary skill in the art of metal material surface
finishing at the time of appellants’ invention
to use the laser shock peening method of hardening the
turbine blade of the Nazmy patent for the purpose of
hardening the blade and thus increasing its fatigue life.
In treating the blade with the laser shock peening, it is
assumed that the entire blade surface is treated. Thus, the
treated surface would include the leading edge and extending
chordwise therefrom. The laser shock peening treatment
inherently produces the region of compressive residual
stresses on the treated surface (answer, page 4).
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