The team of Professor Wang Xiaodong of Shanghai Jiaotong University has made important progress in the performance improvement and mechanism of duplex stainless steel

Recently, the team of Professor Wang Xiaodong from the School of Materials Science and Engineering of Shanghai Jiao Tong University published the latest research results "Study on the deformation mechanism" on the performance enhancement and deformation mechanism of bimodal duplex stainless steel in the international top journal "Acta Materialia" in the field of metal materials.
of a high-nitrogen duplex stainless steel with excellent mechanical properties originated from bimodal grain design” (https://
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The lightweight requirements of the automotive industry and the "longer service life" regulations put forward by European countries for new energy buses have put forward higher requirements on the strength and corrosion resistance of structural steel
.

Figure 1.
(a) True stress-strain curve (b) XRD patterns of samples before and after deformation

Figure 2.
(a) EBSD image of annealed sample (b) EBSD image of rolled sample

Figure 3.
Microstructural characteristics of undeformed specimens

Figure 4.
(a)(b) BF-TEM image of the as-rolled specimen after deformation (c) annealed specimen after deformation (d) EBSD image of the as-rolled specimen after deformation

Figure 5.
TEM image of the ferrite phase in the as-rolled specimen after deformation

Figure 6.
Schematic diagram of deformation mechanism of ferrite and austenite grains in as-rolled specimens

In this study, a high nitrogen duplex stainless steel composed of fine-grained austenite and ferrite with bimodal grain distribution was obtained by regulating the cold rolling and recrystallization processes.
The excellent combination of strength and ductility of duplex stainless steel is achieved by enhancing the proliferation and storage capacity of two-phase dislocations rather than relying on the TRIP effect
.