TY - JOUR

T1 - Correlative cross-sectional characterization of nitrided, carburized and shot-peened steels: synchrotron micro-X-ray diffraction analysis of stress, microstructure and phase gradients

T2 - Correlative cross-sectional characterization of nitrided, carburized and shot-peened steels: synchrotron micro-X-ray diffraction analysis of stress, microstructure and phase gradients

AU - Bodner, Sabine C.

AU - Meindlhumer, Michael

AU - Ziegelwanger, Tobias

AU - Winklmayr, Haiko

AU - Hatzenbichler, Thomas

AU - Schindelbacher, Christoph

AU - Sartory, Bernhard

AU - Krobath, Martin

AU - Ecker, Werner

AU - Schell, Norbert

AU - Keckes, Jozef

PY - 2021/2/3

Y1 - 2021/2/3

N2 - Mechanical properties of case modified steels depend decisively on the near-surface gradients of residual stresses, microstructures, phases and chemical composition, which aregenerated by the empirically well-established case-hardening techniques. Currently,however, to obtain the correlation between near-surface structureeproperty gradients,applied hardening process parameters and steels’ overall performance is a very challenging task. In this work, high-energy synchrotron cross-sectional X-ray diffraction(CSmicroXRD) using a pencil beam cross-section of 20x500 mm2 and complementaryanalytical techniques are used to characterize the surface-to-bulk gradient of (i) a plasmanitrided steel W300, (ii) a carburized case hardening steel (grade 18CrNiMo7-6) and (iii) ashot-peened high strength steel, type 300M. CSmicroXRD analysis reveals complex gradients of martensite and austenite phases, residual stresses in both phases, crystallographictexture and the evolution of diffraction peak broadening with a spatial resolution of~20 mm. These parameters are correlated with the gradients of hardness, morphologymicrostructure and with the changes in N and C concentrations and/or retainedaustenite formation/depletion in all three model samples. Finally, the correlative microanalytics approach indicates the complexity of near surface structure-property relationships as well as the importance of innovative cross-sectional characterization, which allows for assessing gradual near-surface physical and/or chemical changes accompanyingthermo-chemical and mechanical surface treatments

AB - Mechanical properties of case modified steels depend decisively on the near-surface gradients of residual stresses, microstructures, phases and chemical composition, which aregenerated by the empirically well-established case-hardening techniques. Currently,however, to obtain the correlation between near-surface structureeproperty gradients,applied hardening process parameters and steels’ overall performance is a very challenging task. In this work, high-energy synchrotron cross-sectional X-ray diffraction(CSmicroXRD) using a pencil beam cross-section of 20x500 mm2 and complementaryanalytical techniques are used to characterize the surface-to-bulk gradient of (i) a plasmanitrided steel W300, (ii) a carburized case hardening steel (grade 18CrNiMo7-6) and (iii) ashot-peened high strength steel, type 300M. CSmicroXRD analysis reveals complex gradients of martensite and austenite phases, residual stresses in both phases, crystallographictexture and the evolution of diffraction peak broadening with a spatial resolution of~20 mm. These parameters are correlated with the gradients of hardness, morphologymicrostructure and with the changes in N and C concentrations and/or retainedaustenite formation/depletion in all three model samples. Finally, the correlative microanalytics approach indicates the complexity of near surface structure-property relationships as well as the importance of innovative cross-sectional characterization, which allows for assessing gradual near-surface physical and/or chemical changes accompanyingthermo-chemical and mechanical surface treatments

U2 - https://doi.org/10.1016/j.jmrt.2021.01.099

DO - https://doi.org/10.1016/j.jmrt.2021.01.099

M3 - Article

VL - 11.2021

SP - 1396

EP - 1410

JO - Journal of Materials Research and Technology

JF - Journal of Materials Research and Technology

SN - 2238-7854

IS - March-April

ER -