Abstrakt:
The article deals with a Topologically Close Packed (TCP) intermetallic phases, which are presented during service operation of some Ni – base superalloys at high temperatures as well as Geometrically Close Packed (GCP) Ni3X phases. Three cast Ni – base superalloys ŽS6K, IN 713 LC and IN 738 were used as experimental materials for TCP calculation and the same alloys including wrought IN 718 alloy for evaluation of Ni3X phases. Influence of TCP and GCP phases on mechanical properties is briefly disscussed as well.