|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Ultrafine Grained Materials IX
||X-16: The Effect of Grain Structure on the Formation of Nitrided Layers in an Austenitic Stainless Steel
||Malgorzata Lewandowska, Agnieszka Krawczynska, Ryszard Sitek
|On-Site Speaker (Planned)
In this work, the samples of austenitic stainless steel 316LVM after hydrostatic extrusion (HE) at room and elevated temperature were nitrided using low-temperature plasma-assisted nitriding at 430°C for 3 hours. Annealed samples with the coarse grain size was used as reference samples. The sample processed at room temperature with a true strain of 2.3 features an uniformly refined microstructure consisting of nanotwins and shear bands on the cross section and a fiber-like microstructure on the longitudinal section. The sample processed at elevated temperature exhibits the microstructure with equiaxial subgrains. The nitriding process results in the formation of nitride layer, whose thickness was significantly influenced by the substrate grain structure with the thinnest layer formed on the sample processed by HE at room temperature. The results are discussed in terms of the role different types of grain boundaries as fast diffusion paths as well as trapping sites for diffusing nitrogen atoms.