Abstract
Effect of heat treatment on the structure of Nickel-base superalloy IN-100 prepared by liquid phase sintering and swaging was investigated.
The results obtained were as follows:
(1) It was ascertained that the exothermic reaction (1483-1408 K) found during equilibrium solidification is due to the precipitation of γ', and this γ' phase can be dissolved in the same temperature range during heating (the sintered and swaged specimen).
(2) Recrystallized grains in the specimen annealed at 1423 K were very fine, because coarse γ' particles remained. While growth of recrystallized grains was observed in the specimen annealed at 1473 K, because most of γ' particles dissolved.
(3) The structure formed at grain boundary by incipient melting (1498-1523 K) during sintering process was absorbed into matrix by holding below 1498 K. While the structure changed its composition with holding time at 1513 K, and approached to the equilibrium structure which contained a Zr enriched phase.
