The Effect of Second Population NbC Carbides on The Shear Localisation in a Nb-Modified AISI 410 Stainless Steel
(2016) EMMC15 – 15th European Mechanics of Materials Conference — Location: Brussels, Belgium (7.September.2016)
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- Authors
Miotti Bettanini, Alvise 
- Abstract
- Automotive industry is facing an urgent demand to meet stringent regulations in term of gas emission and safety of motor vehicles. This drives an increasing research effort towards the development of new, strongest materials for automotive applications. Martensitic stainless steels (MSS) are valid candidates as they present a good combination of mechanical and functional properties. However, these steels show limited fracture strain under certain loading conditions like three-point bending. The fracture strain is controlled by the evolution of ductile damage as the material is plastically deformed, which is strongly dependent on the microstructural features of the steel like ferrite and martensite phase fraction and carbides distribution. These heterogeneities are critical for the onset of plastic instability and damage localisation at the microscale, which translates to macro-scale shear bands and slant failure under three-point bending conditions. The role of the distribution of the first and second population carbides on plastic instability in a Nb-modified AISI 410 MSS is discussed. A 3D “synthetic” microstructure is reconstructed using statistical information of the distribution of nanoscale NbC carbides from scanning electron microscopy (SEM) images. The damage mechanism is then modelled with finite element method, in which primary micro-scale Cr23C6 carbides are modelled explicitly and the effect of nanoscale NbC carbides is included through a modified Gurson-Tvergaard-Needleman (GTN) model. This set-up captures the shear localisation and void sheeting between primary carbides that cause plastic instability at larger scale. Finally, the cell model results are used to calibrate a full size model of a uniaxial tensile sample to reproduce the mascroscopic behaviour observed experimentally.
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Citations
Miotti Bettanini, A., Delannay, L., Jacques, P., & Pardoen, T. (2016). The Effect of Second Population NbC Carbides on The Shear Localisation in a Nb-Modified AISI 410 Stainless Steel. EMMC15 – 15th European Mechanics of Materials Conference, Brussels, Belgium. https://hdl.handle.net/2078.5/223776