In situ analysis of cryogenic strain of AISI 316L stainless steel using synchrotron radiation

• Published in: Cryogenics (Guildford) Vol. 105; p. 103020
• Main Authors: Crivoi, Maicon Rogerio, Hoyos, John Jairo, Izumi, Marcel Tadashi, de Aguiar, Denilson José Marcolino, Namur, Ricardo Sanson, Terasawa, Ana Luisa, Cintho, Osvaldo Mitsuyuki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01-01-2020; Elsevier BV
• Subjects: Austenite; Austenitic stainless steels; Cryogenic deformation; Cryogenic temperature; Hardening rate; Martensite; Martensitic transformations; Microstrain; Room temperature; Stacking fault energy; Stainless steel; Strain analysis; Synchrotron radiation; Temperature; Tensile strength; Tensile tests; TRIP; UNS S31603; Work hardening; XRD; TRIP; UNS S31603; Cryogenic deformation; Austenite; Stacking fault energy; XRD; Martensite
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/j.cryogenics.2019.103020

•The decrease in temperature changed the kinetics of the martensitic transformation.•Dynamic recovery is lower at cryogenic temperature than at room temperature.•The threshold strain is related to the intensive formation of α′ martensite.•The transformation rate is highest at around 35% of martensite at low temperatures.
AISI 316L austenitic stainless steel was tested by simultaneous uniaxial tensile tests and X-ray diffraction measurements at room and cryogenic temperatures. The decrease in temperature reduced the stacking fault energy, which increase the rate of the martensitic transformation. This led to an intensive formation of martensite during the early stage of deformation, and consequently induced a discontinuous yielding. The tensile strength at cryogenic temperature was higher than that obtained at room temperature, while the steel ductility did not change significantly. This behavior could be associated with the Transformation Induced Plasticity (TRIP) effect since the formation of α′ martensite increased the work hardening rate. In addition, the threshold strain for the onset of discontinuous yielding seems to be related to the lattice microstrain of austenite and the intensive formation of martensite.