Hall–Petch behaviour of 316L austenitic stainless steel at room temperature

Abstract

The room temperature plastic deformation behaviour of two different batches (with differences in chemical composition) of 316L austenitic stainless steel has been studied. By thermomechanical treatments, a wide range of grain sizes varying from 2 . 7 to 64 . 0 m m was obtained in this study. The different microstructural parameters, such as grain size, distribution of grain size and shape, dihedral angle distribution, and grain aspect ratio were measured for annealed and deformed specimens of the two batches. The Hall ± Petch behaviour of batch 1 showed two distinctly different linear regions, one in the ® ne grain size range (d< 6 m m) and the other in the coarse grain size range (dù 6 m m). The Hall ± Petch parameter K H (e) was signi® cantly higher in the ® ne grain regime than coarse grain regime at all strains. Hardness measurements were also performed across the grain at different strain levels. The applicability of the Hall ± Petch relationship was assessed in batch 1 and batch 2. It was observed that the Hall ± Petch relationship was applicable in the coarse grain regime and Kocks composite relationship in the ® ne grain regime of batch 1. In batch 2 of 316L austenitic stainless steel, a single linear Hall ± Petch relationship could describe the deformation behaviour over the entire range of grain size (from 2 . 9 to 46 m m) studied. The variation of the Hall ± Petch and Kocks composite parameters with strain was discussed in terms of changes in the microstructural parameters.MST/5014

Estimation of Melt Pool Dimensions, Thermal Cycle, and Hardness Distribution in the Laser-Engineered Net Shaping Process of Austenitic Stainless Steel

“…The available literature suggests a wide range of possible values of r 0 and k y for SS316, and selection of the most suitable values of r 0 and k y applicable to the multilayer deposits of SS316 has remained a puzzle. In a recent experimental study, Singh et al [30] reported the values of r 0 and k y as 150.8 and 575 MPa (lm) 0.5 , respectively, for well-annealed cold-rolled SS316 and the same are followed in the present work. The layerwise hardness (H v ) is calculated as [27,28,[30][31][32] …”

“…This is because, though part of the same grain, small misorientation between the neighboring cells, and, more importantly, microsegregation within the cell core and at the boundaries, would further impede the dislocation motion. [27][28][29][30] A Hall-Petch like relation (Eq. [2]) is used next to estimate the yield strength (r y ) with d g as the cell spacing and k y interpreted as a measure of cell boundary resistance to the dislocation motion.…”

Direct laser deposition with different types of 316L steel particle: A comparative study of final part properties

“…[30][31][32] Although this expression has been shown to be an approximation, but holds good for the microstructural scale present in these walls and in the absence of phase change or precipitation effects. 33 Corrosion resistance Figure 13 shows the corrosion rate of all samples. Walls made from powder generally displayed better corrosion resistance: there were only two exceptions to this from the 16 parameter combinations tested.…”

Impact response of additively manufactured metallic hybrid lattice materials

“…Stainless steel 316L is attractive for this application due to its high strength and strain hardening characteristics, and its conduciveness to additive manufacturing. Laser processing of this material has an additional benefit of grain size reduction, and the formation of fine scale subgrain solidification structures as detailed above, leading to Hall-Petch strengthening [25,43,44]. A standard tensile dogbone specimen with a gauge section of width 3 mm, length 20 mm and thickness 1 mm was manufactured using the same SLM process as the cellular specimens.…”