Theoretical phase-field-method-based model of the γ phase dissolution of base metals in duplex stainless steels

Abstract

Duplex stainless steel (DSS) is vulnerable to changes in the α/γ volume ratio due to the dissolution of various compounds during multi-pass welding. Thus, prediction of this dissolution behavior is key for the development of effective manufacturing strategies. In this study, the γ phase dissolution behavior of different types of DSSs was predicted using the phase-field method. The kinetics of the DSS dissolution phenomena were evaluated theoretically and experimentally through optical and scanning electron microscopy. DSSs with different compositions were evaluated to achieve satisfactory correlation. The results of the theoretical analysis revealed the relationship between the kinetic constant and the temperature and elucidated the kinetics of the α/γ phase transformation. The relationships were adjusted by determining coefficients to improve the correlation with the experimental results. This corrected calculation was then applied to another lean DSS to confirm the generality of the solution. The experimental and kinetics-based theoretical results of this study could serve as a resource for predicting the γ phase dissolution behavior of DSSs.