On the interstitial induced lattice inhomogeneities in nitrogen-expanded austenite. (August 2020)

• Record Type: Journal Article
• Authors: Tao, Xiao; Qi, Jiahui; Rainforth, Mark; Matthews, Allan; Leyland, Adrian
• Is Part Of: Scripta materialia. Number 185(2020)
• Page Start: 146
• Page End: 151
• Publication Date: 2020-08
• Subjects: Nitriding -- Expanded austenite -- Shear banding -- Martensitic phase transformation -- High-resolution electron microscopy (HREM); Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2020.04.045
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: Lattice inhomogeneities, i.e. nitrogen interstitial-induced hexagonal-close-packed martensite (HCP-εN ) and shear bands, can form in face-centred cubic nitrogen-expanded austenite (FCC-γN ) synthesised on Fe-Cr-Mn and Fe-Cr-Ni austenitic stainless steel (ASS) using triode-plasma nitriding (TPN). Homogenous elemental distribution between HCP-εN and FCC-γN supports the displacive shear transformation mechanism proposed for a high-Mn, low stacking fault energy ASS under nitrogen interstitial-induced deformation. While resulting from transformation-induced plasticity, HCP-εN exhibits similar lattice expansion behaviour to the parent FCC-γN . However, inhomogeneous elemental distributions in the shear bands formed in γN layers on a 400°C TPN-treated high-Ni ASS indicate local migration of substitutional elements. Graphical abstract: Image, graphical abstract