The possibility of reducing the linear thermal expansion coefficient (
LTEC) of heavy tungsten-base alloys by replacing the binder by one pos
sessing Invar properties is studied. Use of Invar type alloys of the F
e-Ni and Fe-Co-Cr types as binders makes it possible to prepare heavy
alloys with lower LTEC than for the base (tungsten). Tungsten dissolut
ion in the binder is the main factor which restricts the LTEC of heavy
alloys with an Invar binder.