In-situ EBSD study of the coordinated deformation behavior of 2205 duplex stainless steel fabricated via laser powder bed fusion during the tensile process

Abstract

Duplex stainless steels (DSSs) produced via laser powder bed fusion (LPBF) exhibit excellent strength and plasticity compatibility. In this study, in-situ electron backscatter diffraction (EBSD) was employed to investigate the coordinated deformation behavior of 2205 DSSs fabricated by LPBF with heat treatment at 1050 °C for 1 h, including strain distribution behavior and mechanism of stress concentration release. The results indicate that the initial deformation of LPBF samples is primarily concentrated in the austenite phase. As the tension progresses, austenite gradually transitioned to hard orientation, and the strain in austenite can pass through the phase boundary into the ferrite grain. To coordinate the deformation, ferrite transitioned to soft orientation through rotation towards the slip systems of {110}<−111> and {1–21}<111>. The stress concentration in ferrite can be alleviated by forming dislocation walls and cells through planar and cross-slip dislocations. In contrast, the stress concentration in austenite can be released by stacking faults and deformation twins. Compared to the as-cast samples, the yield strength of LPBF samples is improved from 472 ± 13 to 641 ± 17 MPa due to fine grain strengthening and dislocation strengthening. This study offers guidance for further enhancing the strength and plasticity of materials prepared by LPBF.