The strain-rate dependence of the Hall-Petch effect in two austenitic stainless steels with different stacking fault energies

Publication date: Available online 19 April 2019Source: Materials Science and Engineering: AAuthor(s): Sergey V. Astafurov, Galina G. Maier, Evgenii V. Melnikov, Valentina A. Moskvina, Marina Yu. Panchenko, Elena G. AstafurovaAbstractUsing thermal-mechanical treatments, specimens with different grain sizes were produced for two Cr-Ni-based austenitic stainless steels with different stacking fault energies (analogues of AISI 316L and AISI 321 steels). The effect of strain-rate on the tensile deformation behavior and strength properties was evaluated for these steels. In given grain size interval, (3–73)μm for 316 steel and (0.2–32)μm for 321 steel, the yield strength σ0.2varies with grain size D in accordance with Hall-Petch relationship σ0.2=σ0+kHPD−1/2. The Hall-Petch coefficient kHP depends on steel composition (stacking fault energy) and possesses higher value for 321 steel as compared to 316 steel. Increase in strain-rate in the interval of 1.0 × 10−4 s−1 to 1.0 × 10−2 s−1 causes growth in stress σ0, but weakly changes coefficient kHP in Hall-Petch relationship: 322–327 MPa × m0.5 for 316 steel and 404–413 MPa × m0.5 for 321 steel. The strain-rate dependence of the constants in Hall-Petch relationship was discussed in terms of deformation mechanism and dislocation arrangement in both steels.
Source: Materials Science and Engineering: A - Category: Materials Science Source Type: research