Appeal No. 2002-1752
Application 09/180,464
Reiso’s method is that if the alloy is cooled too rapidly before
extrusion, the properties of the finished product may
deteriorate. Specification, page 2, third paragraph. For
example, the finished product may exhibit a reduction in
mechanical properties after hardening. Id.
According to appellants,
[t]he present invention is based on new
knowledge on alloys from eutectic alloy
systems; it has been found that if the
cooling rate during the production of the
alloy is too high, a new precipitation
reaction, which has not previously been
demonstrated, will have a major effect on the
properties of the alloy, such as tensile
strength and possibly the anodising
properties, in the finished product.
Id., page 5, second paragraph. More specifically, appellants
have found that if the cooling rate during production of the
alloy is too high, the resultant extrudates have a high number of
small (10-30 mm) dispersoid particles. Appeal Brief, page 4,
third paragraph. The dispersoid particles have a negative impact
on the tensile strength in the resultant extrudates. Id. at
paragraph 4.
Appellants have discovered that it is possible to
obtain extrudates having high tensile strength values by cooling
the workpiece, after the reheating step, “at a cooling rate
4
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