SELF AND INTERACTION ELASTIC ENERGY OF γ` PRECIPITATES IN A-286 STEEL

Mati Shmulevitsh 1,2 Yoav Snir 2 Roni Z. Shneck 1
1Material Engineering, Ben-Gurion University of the Negev, Beer-Sheva
2Material Engineering, NRCN, Beer-Sheva

The iron-base superalloy A-286 with nominal composition 25Ni-15Cr is a corrosion, oxidation and heat resistant stainless steel, which is widely used for intermediate temperature applications. This austenitic stainless steel is precipitation hardened mainly by ordered cubic γ`-Ni3(Ti, Al) phase.

We study the elastic fields, elastic interaction and elastic energy associated with the γ`-Ni3Ti precipitates, taking into account the difference between the elastic constants of the matrix and the precipitates in two different approaches: the first is the equivalent inclusion approach suggested by Eshelby and the other is an integral equation solved by an iterative method suggested by Lee et al. and Chu et al..

The elastic energy in the heterogeneous precipitate provides explanation to the observed spherical shape of the precipitates and to their ordering along the crystallographic axes with short interparticle distances. These interparticle distances were verified by experimental observations.









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