首页|(111674)Signifcant effects of grain size on mechanical response characteristics and deformation mechanisms of metastable austenitic stainless steel
(111674)Signifcant effects of grain size on mechanical response characteristics and deformation mechanisms of metastable austenitic stainless steel
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NSTL
Elsevier
Grain size of a 304 austenitic stainless steel was tuned via deformation-induced martensite transformation and austenite reversion annealing, and the signifcant effects of grain size on mechanical properties, strain hardening behavior, deformation mechanisms were studied. The results showed that grain refnement strengthening signifcantly increased the yield strength from 235 MPa (~20 μm) to 1030 MPa (~200 nm), meanwhile, the interaction of Lüders deformation and deformation-induced martensite transformation realized the stable propagation of Lüders bands, leading to a considerable total elongation (above 30%). It was inferred that martensitic transformation was enhanced with a decrease in grain size. The underlying reasons were attributed to the formation of carbide precipitation (M23C6) and the change of martensite nucleation sites depending on grain size. In coarse grains, α'-martensite formed at shear bands with or without the aid of ε-martensite, whereas α'-martensite mainly nucleated at grain boundaries and deformation twins in ultrafne austenite grains. Besides TRIP effect and dislocation glide, TWIP effect also became one of the dominate deformation mechanism with the decrease in austenite grain size.
Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
The State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China
NSTL
Elsevier
