Appeal No. 2002-0183
Application No. 09/379,570
zirconium as required by the appealed claims. The examiner
reasons, however, that since Bergsma discloses that zirconium is
typically used in aluminum alloys for grain refining, and Wade
discloses the addition of zirconium to improve the combination of
high strength and high toughness in aluminum alloys, it would
have been obvious for one of ordinary skill in the art to add
zirconium to the aluminum-magnesium-silicon alloy of Bergsma to
improve fracture toughness. Also, although Bergsma does not
disclose the claimed Charpy energy and volume percent per unit
area for the alloy, the examiner concludes that the alloy
resulting from the combination of Bergsma and Wade would
necessarily exhibit the same properties.
The problem with the examiner’s rationale, as properly
articulated by appellants, is that one of ordinary skill in the
art would not have had the requisite motivation to add zirconium
to the aluminum alloy of Bergsma. Bergsma, while acknowledging
that zirconium is a conventional component in aluminum alloys,
assuages the use of zirconium in the inventive alloy and obtains
a dendritic microstructure. Wade, on the other hand, discloses a
zirconium-containing aluminum alloy having a highly elongated
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