Appeal No. 2004-0109
Application 09/324,549
of alloys B and D are virtually identical at Aging Conditions 4 through 7, including Aging
Condition 6, the so-called “T8 condition,” and within 1 ksi at Aging Conditions 2, 3 and 8; and
that the ksi of alloys C and D are virtually identical at Aging Condition 8, the difference between
alloys C and D being about 1 ksi at Aging Condition 7, about 2 ksi at Aging Conditions 2, 3 and
6, and about 3 ksi at Aging Conditions 4 and 5.
Based on the limitation “the alloy is capable of attaining a yield strength (L) above about
80 ksi” (emphasis supplied), we find that alloys B and D achieved this level when worked at
Aging Conditions 2 through 5, 7 and 8, alloys B and D being at about 78 ksi when worked at
Aging Condition 6, with alloy C being at about 80 ksi for each of the Aging Conditions.
We find no explanation in the specification of the significance of the differences in the
Aging Conditions employed. Appellants disclose that “t]he aluminum alloy comprises . . . from
about 0.10 to about 0.99% lithium” and that “[i]t has been found . . . ancillary additions of low
levels of lithium to aluminum-zinc alloys provided a high strength . . . that exhibits good fracture
toughness . . . over aluminum-zinc alloys without lithium additions and those aluminum-zinc
alloys having lithium additions above 1.0 wt %” (page 1, line 27, to page 2, line 7). Appellants
further disclose with respect to “strength” that “the alloy of the invention has good strength . . . .
The yield strength (L) of the alloys of the invention are preferably above about 80 ksi and more
preferably above about 85 ksi” (id., page 4, lines 7-10).
Appellants, in describing the results shown in specification FIG. 1, state only that “[i]t
will be seen that the alloys having lithium additions[, that is, alloys B, C and D,] exhibit greater
strength than those without lithium[, that is, alloy A], while at the same time exhibiting thermal
stability” (id., page 9, lines 15-17). No distinction in result between alloys B, C and D is set
forth in the specification, the distinction being drawn only with respect to alloys B, C and D as a
whole vis-à-vis alloy A in support of the disclosure of the disclosed aluminum alloy having
lithium between 0.10 and 0.99 wt % lithium. There is no other evidence in the specification with
respect to alloy D.
With respect to the disclosure that “[t]he alloy of the invention will also preferably have a
combination of (i) good strength and (ii) fracture toughness of preferably (i) above 80 ksi and (ii)
above 30 ksi√inch” (specification, page 4, lines 13-16), and the claimed limitation “the alloy is
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