The possible role of impurities in affecting the ductility of intermet
allic compounds is reviewed using the behavior of three different comp
ounds as examples: Ni3Al, TiA(l), and NiAl. It is shown that the roles
of crystal structure, environment and microstructure are at least as
important as impurities and that the effects of impurities can only be
clearly seen after these other factors are also controlled in the exp
eriment.