Element partitioning and electron backscatter diffraction analysis from feeding wire to as-deposited microstructure of wire and arc additive manufacturing with super duplex stainless steel

Abstract

The redistribution of alloying elements and the crystallographic characterizations in wire and arc additive manufactured (WAAM) super duplex stainless steel (SDSS) was investigated from the wire to the final as-deposited structure. The results showed that elemental partitioning between austenite and ferrite was suppressed in the last layer and the solidified droplet. The high Ni content but low Cr and N contents in the initial state of the intragranular austenite (IGA) confirmed the predominance of the chromium nitrides acted as the nucleation sites. Gathering of nitrogen was found more distinct in the coarsening IGA, Widmanstätten austenite (WA) than the grain boundary austenite (GBA). The columnar epitaxial ferrite presented a strong <001> texture in the deposition direction, while the <001> and <101> orientations was found in the austenite. Random orientations of the intragranular secondary austenite was revealed. The Rotated Cube texture of the austenite grains were consumed by the "recrystallization" textures (Brass, Rotated Brass, Cu, R, E, and F) caused by the austenite reformation. The low-angle interphase boundaries between austenite and ferrite were predominated in the as-deposited wall, and, at which, the K-S orientation took the crucial part. A Taylor factor analysis revealed that through fabrication via additive process, the austenite became oriented "harder" and contributed most to good mechanical properties. The textured microstructure contributed about a 2.6% higher engineering strain in the Z direction and a 27.8 MPa higher yield strength in the X direction.

Influence of Different Beam Oscillation Patterns in Electron Beam Welding of Niobium Sheets with Different Thickness

“…The Taylor factor distribution obtained by the EBSD is also studied to evaluate the resistant ability to the plastic deformation of crystals [ 44 ]. Figure 12 shows the Taylor factor distribution maps for loading direction in the tensile tests.…”

Wire Laser Metal Deposition Additive Manufacturing of Duplex Stainless Steel Components—Development of a Systematic Methodology

“…It has been demonstrated in this and other studies that additive manufacturing can be used to build DSS components, although achieving a desired microstructure and properties can be a challenge, as discussed in the introduction [ 13 , 14 , 15 , 16 , 17 , 18 , 23 , 24 , 25 , 26 ]. Figure 12 summarizes some important factors during production, the tools available to predict the resulting microstructure, and important properties that need to be controlled.…”

“…In all cases, an excessive amount of ferrite was a problem in the microstructures of the additively manufactured parts, and a post-heat treatment was necessary to balance ferrite and austenite fractions. Wire-arc additive manufacturing (WAAM) of DSS has also attracted widespread interest due to the affordable equipment and its high deposition rate [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Zhang et al [ 22 ] observed an unbalanced microstructure with a high fraction of austenite in WAAM of super DSS.…”

Wire laser metal deposition of 22% Cr duplex stainless steel: as-deposited and heat-treated microstructure and mechanical properties

“…In powder bed fusion AM with selective laser melting (SLM) [9,[17][18][19], an excessive amount of ferrite formation is a problem and post-heat treatment has been necessary to balance the ferrite and austenite ratio. Wire-arc additive manufacturing of DSS has also attracted widespread interest due to the affordable equipment and its high deposition rate [20][21][22][23][24].…”