Microstructural studies on rapidly solidified alloy 600

Abstract

Rapid solidification processing (RSP) is known to generate unusual microstructures which may be associated with several superior properties as compared with the conventionally processed materials. Due to its many desirable effects on microstructure, RSP is being increasingly used in the processing of many types of alloys, including the nickel based superalloys. It has been observed that in the precipitation hardenable nickel base superalloys, like Alloy 625, the excess vacancy concentration in the RSP microstructure not only accelerates the kinetics of formation of the desirable strengthening precipitate phase during aging but also brings about a relatively rapid coarsening of these particles and promotes the precipitation of the comparatively undesirable equilibrium phases. In some alloys it has been observed that the precipitation reaction in the RSP microstructure differs from that in the conventionally processed microstructure and leads to the formation of a different structure and or morphology of the precipitate phase. It is interesting to compare the microstructure of the conventionally processed and the RSP microstructure in solid solution strengthened alloys such as Alloy 600. In the present work, the RSP microstructure of the commercial, nickel base wrought superalloy, Alloy 600 has been compared with the microstructure of the conventionally processed andmore » solution treated alloy.« less