On the origin of the tensile flow stress in the stainless steel AISI 316L at 300 K: Back stress and effective stress

Tensile specimens of Type 316L stainless steel having grain sizes in the range 3.1–86.7 μm were deformed to 34% strain at temperatures 24, 400 and 700°C and strain rate 1 × 10−4s−1 to investigate the Hall-Petch (H-P) relationship, the nature of stress-strain curves and the substructure development. Upto ∼5% strain the H-P relationship exhibits bi-linearity whereas the single Hall-Petch relation is exhibited at larger strains. The presence of bi-linearity is explained by the back stress associated with the difference in the dislocation densities in the vicinity of grain boundary and in the grain interior. The log stress (σ)-log strain (e) plots depict three regimes and follow the relationship σ = Ken in each regime, but with varying magnitudes of the strength coefficient (K) and strain-hardening exponent (n).

On the Hall-Petch relationship and substructural evolution in type 316L stainless steel

Deformation mechanisms in an austenitic single-phase duplex microstructured steel with nanotwinned grains

Influence of temperature and strain rate on tensile work hardening behaviour of type 316 LN austenitic stainless steel

The true stress (σ)–true plastic strain (ɛ) data of a type 316LN austenitic stainless steel tested at nominal strain rates in the range 3×10-5–3×10-3 s-1 and temperatures of 300–1123 K were analysed in terms of flow relationships proposed by Hollomon, Ludwik, Swift, Voce, and Ludwigson. The applicability of the particular flow relationship is discussed in terms of ‘complete’ and ‘applicable’ range fits of the experimental σ–ɛ data. At all strain rates, in the case of the complete range fit, the Ludwigson equation followed the stress–strain data most closely at 300 K, while in the temperature range 523–773 K, the flow behaviour was described equally well by both the Ludwigson and Voce equations. In the temperature range 823–1023 K, the Voce equation described the flow behaviour most accurately in the case of the complete range fit of σ–ɛ data at all strain rates. The analysis of σ–ɛ data employing the Ludwigson equation in the applicable range fit covering low and intermediate strains, and the Holl...

Tensile stress–strain and work hardening behaviour of 316LN austenitic stainless steel

Tensile specimens of type 316L stainless steel with a grain size of 5.0 μm have been deformed at a constant strain rate of 10−3 s−1 over the temperature range 21–900°C and by differential strain-rate test technique over strain rates from about 10−5 to 10−3 s−1 at temperatures in the range 750–900°C. The normalized yield and flow stresses against temperature plots exhibit three regions. While in regions I and III the stresses decrease with increasing temperature, they increase with increasing temperature in region II. Transmission electron microscopy studies on deformed specimens show that at small strains the dislocations generated at grain boundaries have characteristic distributions: in region I the dislocations are confined to the vicinity of the grain boundary, in region II the dislocations are spread into the grain interior, and in region III the dislocations rearrange to form walls. The evolution of substructure and the work-hardening behaviour are explained by considering both intragranula...

K. McTaggart

Papers

Study on the substructure evolution and flow behaviour in type 316L stainless steel over the temperature range 21-900°C