A niobium-silicide refractory metal intermetallic composite adapted for use in
a turbine component. The niobium-silicide refractory metal intermetallic composite
comprises: between about 19 atomic percent and about 24 atomic percent titanium;
between about 1 atomic percent and about 5 atomic percent hafnium; between about
16 atomic percent and about 22 atomic percent silicon; between about 7 atomic percent
and about 14 atomic percent chromium; from about 1.5 atomic percent to about 3
atomic percent tin; and a balance of niobium. The niobium silicide refractory intermetallic
composite contains a tetragonal phase, which comprises a volume fraction from 0.35
to 0.5 of the niobium silicide refractory intermetallic composite, and a hexagonal
M3Si5 silicide phase (wherein M is at least one of Nb and
Hf) which comprises a volume fraction comprises less than 0.25 of the niobium silicide
refractory intermetallic composite. A ratio of the sum of atomic percentages of
niobium and tantalum present in said niobium silicide refractory intermetallic
composite to the sum of atomic percentages of titanium and of hafnium present in
said niobium silicide refractory intermetallic composite has a value from 1.5 to 2.0.
