scholarly journals In Situ Neutron Diffraction Study of Phase Transformation of High Mn Steel with Different Carbon Content

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 101
Author(s):  
Youngsu Kim ◽  
Wookjin Choi ◽  
Hahn Choo ◽  
Ke An ◽  
Ho-Suk Choi ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Neutron Diffraction ◽  
Strain Hardening ◽  
High Strain ◽  
Tensile Deformation ◽  
Austenite Phase ◽  
Transformation Rate ◽  
Ε Martensite ◽  
In Situ Neutron Diffraction

In situ neutron diffraction was employed to examine the phase transformation behavior of high-Mn steels with different carbon contents (0.1, 0.3, and 0.5 wt.%C). With increasing carbon contents from 0.1 C to 0.5 C, the austenite phase fraction among the constituent phases increased from ~66% to ~98%, and stacking fault energy (SFE) increased from ~0.65 to ~16.5 mJ/m2. The 0.1 C and 0.3 C steels underwent phase transformation from γ-austenite to ε-martensite or α’-martensite during tensile deformation. On the other hand, the 0.5 C steel underwent phase transformation only from γ-austenite to ε-martensite. The 0.3 C steel exhibited a low yield strength, a high strain hardening rate, and the smallest elongation. The high strain hardening of the 0.3 C alloy was due to a rapid phase transformation rate from γ-austenite to ε-martensite. The austenite of 0.5 C steel was strengthened by mechanical twinning during loading process, and the twinning-induced plasticity (TWIP) effect resulted in a large ductility. The 0.5 wt.% carbon addition stabilized the austenite phase by delaying the onset of the ε-martensite phase transformation.

scholarly journals In situ neutron diffraction under tensile deformation for patented pearlite steels

2004 ◽  
Vol 2004 (0) ◽  
pp. 89-90
Author(s):  
Tomoya Shinozaki ◽  
Satoshi Morooka ◽  
Tetsuya Suzuki ◽  
Yo Tomota
Keyword(s):  
Neutron Diffraction ◽  
Tensile Deformation ◽  
In Situ Neutron Diffraction

scholarly journals Tracing Phase Transformation and Lattice Evolution in a TRIP Sheet Steel under High-Temperature Annealing by Real-Time In Situ Neutron Diffraction

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 360 ◽  
Author(s):  
Dunji Yu ◽  
Yan Chen ◽  
Lu Huang ◽  
Ke An
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Neutron Diffraction ◽  
Real Time ◽  
Retained Austenite ◽  
Sheet Steel ◽  
Carbon Diffusion ◽  
Structure Evolution ◽  
In Situ Neutron Diffraction

Real-time in situ neutron diffraction was used to characterize the crystal structure evolution in a transformation-induced plasticity (TRIP) sheet steel during annealing up to 1000 °C and then cooling to 60 °C. Based on the results of full-pattern Rietveld refinement, critical temperature regions were determined in which the transformations of retained austenite to ferrite and ferrite to high-temperature austenite during heating and the transformation of austenite to ferrite during cooling occurred, respectively. The phase-specific lattice variation with temperature was further analyzed to comprehensively understand the role of carbon diffusion in accordance with phase transformation, which also shed light on the determination of internal stress in retained austenite. These results prove the technique of real-time in situ neutron diffraction as a powerful tool for heat treatment design of novel metallic materials.

In situ neutron diffraction study of α–γ Fe–Cr–Ni alloys under tensile deformation

2001 ◽  
Vol 49 (13) ◽  
pp. 2471-2479 ◽  
Author(s):  
S. Harjo ◽  
Y. Tomota ◽  
P. Lukáš ◽  
D. Neov ◽  
M. Vrána ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Diffraction Study ◽  
Tensile Deformation ◽  
Neutron Diffraction Study ◽  
Ni Alloys ◽  
In Situ Neutron Diffraction

scholarly journals In Situ Observation for Deformation-Induced Martensite Transformation (DIMT) during Tensile Deformation of 304 Stainless Steel Using Neutron Diffraction. PART I: Mechanical Response

2020 ◽  
Vol 4 (3) ◽  
pp. 31
Author(s):  
Yusuke Onuki ◽  
Shigeo Sato
Keyword(s):  
Stainless Steel ◽  
Neutron Diffraction ◽  
Martensite Transformation ◽  
Tensile Deformation ◽  
Austenite Phase ◽  
Austenitic Steels ◽  
304 Stainless Steel ◽  
Proton Accelerator ◽  
In Situ Observation

304 stainless steel is one of the most common stainless steels due to its excellent corrosion resistance and mechanical properties. Typically, a good balance between ductility and strength derives from deformation-induced martensite transformation (DIMT), but this mechanism has not been fully explained. In this study, we conducted in situ neutron diffraction measurements during the tensile deformation of commercial 304 stainless steel (at room temperature) by means of a Time-Of-Flight type neutron diffractometer, iMATERIA (BL20), at J-PARC MLF (Japan Proton Accelerator Research Complex, Materials and Life Science Experimental Facility), Japan. The fractions of α′-(BCC) and ε-(HCP) martensite were quantitatively determined by Rietveld-texture analysis, as well as the anisotropic microstrains. The strain hardening behavior corresponded well to the microstrain development in the austenite phase. Hence, the authors concluded that the existence of martensite was not a direct cause of hardening, because the dominant austenite phase strengthened to equivalent values as in the martensite phase. Moreover, the transformation-induced plasticity (TRIP) mechanism in austenitic steels is different from that of low-alloy bainitic TRIP steels.

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