Author(s): Conde, F. F. ; Avila, J. A. [UNESP] ; Oliveira, J. P. ; Schell, N. ; Oliveira, M. F. ; Escobar, J. D.
Date: 2022
Persistent ID: http://hdl.handle.net/11449/221899
Origin: Oasisbr
Subject(s): Additive manufacturing; Austenite reversion; In-situ X-ray diffraction; Laser-based Powder Bed Fusion; Maraging steel
Made available in DSpace on 2022-04-28T19:41:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-10-01
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Nuclear Fuel Cycle and Supply Chain
During laser-based powder bed fusion, the non-equilibrium solidification conditions promote local elemental segregation, leading to a characteristic microstructure composed of cellular walls. These walls can display either low carbon BCC martensite or FCC retained austenite crystal structures, thus affecting the subsequent isochronal or isothermal martensite to austenite phase transformation mechanisms. In the present study, the effect of the non-homogeneous as-built microstructure on the martensite-to-austenite reversion phenomena was studied for a 18Ni maraging steel fabricated by laser-based powder bed fusion. In-situ synchrotron X-ray diffraction was used to retrieve the austenite volume fraction and lattice parameter evolution during the physical simulation of continuous heating cycles to the austenitic field; and during isothermal tempering cycles throughout the inter-critical tempered martensite + austenite (α’ + γ) field. The as-built microstructure resulted in the expansion of the inter-critical α’ + γ field during very slow heating rates. This was associated to the synergic effects of compositional segregations (anticipating reversion) and pre-existing retained austenite (delaying solubilization). During conventional inter-critical tempering, the as-built microstructure did not fundamentally alter the austenite reversion kinetics, resulting in similar high temperature microstructures at the end of the isothermal stage relative to the solution treated state.
Department of Materials Engineering University of Sao Paulo (USP), Av. Joao Dagnone, 1100 Jd. Sta Angelina
São Paulo State University (UNESP) Campus of São João da Boa Vista, Av. Profa. Isette Corrêa Fontão, 505, Jardim das Flores
Universidad Autónoma de Occidente (UAO), Cali, Calle 25, Vía Cali - Puerto Tejada #115-85 Km 2, Cali
Metallurgical and Materials Engineering Department University of São Paulo, 10 Av.Prof. Mello Moraes 2463
UNIDEMI Department of Mechanical and Industrial Engineering NOVA School of Science and Technology NOVA University Lisbon
Institute of Materials Physics Helmholtz-Zentrum Hereon, Max-Planck-Str. 1
São Paulo State University (UNESP) Campus of São João da Boa Vista, Av. Profa. Isette Corrêa Fontão, 505, Jardim das Flores
CNPq: 142440/2019
Nuclear Fuel Cycle and Supply Chain: UID/EMS/00667/2019
