This article provides an overview of structural changes that occur during the hot working of superalloys and provides insight into the use of precipitated particles and other thermomechanical factors to achieve desired structures. Examples will focus primarily on alloys 718 and 720, which are iron-nickel and nickel-based alloys, respectively. The availability of a second phase to control grain size is a characteristic of some iron-nickel- and nickel-based superalloys that is not usually available to cobalt-based superalloys; processing with and without the use of a precipitated phase that influences microstructures will be illustrated by the use of these examples.

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SOURCE: Forbes, R. M. and L. A. Jackman. “The Structural Evolution of Superalloy Ingots during Hot Working”. JOM. Vol. 51. No. 1. January 1999. Pp. 27-31.