Appeal No. 95-4209
Application No. 07/862,486
disclosure regarding the employment of cobalt in an amount of
9% or below, molybdenum in an amount of 12% or below, tungsten
in an amount of 6% or below and boron in an amount of 0.05% or
less in an alloy can be interpreted as not requiring the
presence of all of the above-mentioned components.
Specifically, Tsuji states (page 3) that:
Particularly, among the precipitation-hardening Ni-
based heat-resistant alloys for forging (which are
currently put to practical use), those which have
the 10 h creep rupture strength of 80MPa or higher at3
871EC contain 10% or more of Co without exception (as
shown in Figure 1).
Unfortunately, Co is an expensive element. If a
precipitation-hardening Ni-based
heat-resistant alloy for forging
is developed with a low Co
content, it will be cost-
efficient.
Cobalt is effective in raising the Young’s modulus of the
alloy at a high temperature and in decreasing the mean thermal
expansion coefficient at a high temperature. See page 10.
Molybdenum and tungsten, on the other hand, are necessary for
effectively reinforcing the base material of the alloy by
solid dissolution. See pages 10 and 11. Also, molybdenum,
like cobalt, is effective in lowering the mean thermal
expansion coefficient. See page 10. According to Tsuji,
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