Microstructure-based multiscale and heterogeneous elasto-plastic properties of 2205 duplex stainless steel welded joints: Experimental and modeling

Abstract

This work aims to reveal the inherent dependency between the heterogeneous microstructure induced by the metallurgical transformation during welding of 2205 duplex stainless steel (DSS) and its macroscopic and microscopic elasto-plastic properties by experiments and models. A multiscale model was developed by combining a macro-constitutive model incorporating the physically-based yield strength and a crystal plasticity model considering both the micro-mechanical properties of two phases and their realistic morphology. The results show that the heterogeneous macro-mechanical properties of base metal (BM), heat affected zone (HAZ), and weld material (WM), as well as their micro-mechanical responses related to phase morphology, ratio, and grain size, can be accurately predicted. The contribution of Peierls–Nabarro stress, solid solution strengthening, grain/phase boundary, and dislocations density on macro-yield and tensile strengths was quantified, and WM was proven to have greater yield and tensile strengths due to the greater contribution of grain refinement and solid solution strengthening. In addition, a transition mechanism of the deformation-bearing phase from austenite to ferrite with the increase of load was proved, and the banded grain boundary austenite (GBA) and its adjacent ferritic grains were prone to plastic-deformation. This work can be used as guidance of structure integrity assessment and welding process optimization for the engineering components of DSS.