Journal Published Online: 28 February 2017
Volume 6, Issue 3

Microstructure Analysis of Segmented Chips of Super Duplex Stainless Steel Sandvik SAF 2507™ Using Electron Microscopy Techniques



Machined chips of Sandvik SAF 2507™ which is a super duplex stainless steel (SDSS), are known to exhibit segmentation. These segmented chips are known to contain primary shear zones (PSZs) and secondary shear zone (SSZs) zones. PSZ regions exhibit adiabatic shear bands (ASBs). To analyze such ASBs, electron backscatter diffraction (EBSD) is an excellent technique. However, due to severe deformation and grains in the range of a few nanometers, the information obtained is limited when using conventional EBSD (c-EBSD) and instead, Transmission Kikuchi Diffraction (TKD)/transmission EBSD (t-EBSD) can be used with great advantage. In this work, TKD and c-EBSD techniques were used to analyze PSZs/ASBs and SSZs regions, respectively. The backscattered electron (BSE) images of PSZs/ASBs clearly showed alternate bands of austenite and ferrite with very fine elongated grains along the shear direction. On the other hand, the SSZs exhibited alternate regions of equiaxed and non-equiaxed or deformed grains. Furthermore, c-EBSD showed that ferrite was significantly recrystallized and austenite was deformed to a great extent. Similar observations were also noticed in the PSZs/ASBs using TKD: that ferrite recrystallizes to a greater extent than austenite. Another interesting observation was that in the regions farther away from the SSZs, the grains adjacent to PSZs/ASBs exhibit higher numbers of low angle grain boundaries (LAGBs) than the grains in the middle of the segments. This could be attributed to higher extent of deformation in the neighboring regions of severely deformed PSZs/ASBs.

Author Information

Raveendra, S.
AB Sandvik Materials Technology, Sandviken, SE
Gustavsson, F.
AB Sandvik Materials Technology, Sandviken, SE
Golpayegani, A.
AB Sandvik Materials Technology, Sandviken, SE
Haraldsson, J.
AB Sandvik Materials Technology, Sandviken, SE
Chai, G.
Div. of Engineering Materials, Linköping Univ., Linköping, SE AB Sandvik Materials Technology, Sandviken, SE
Pages: 10
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Stock #: MPC20160043
ISSN: 2165-3992
DOI: 10.1520/MPC20160043