In-situ Neutron Diffraction Analysis of Crystal Plasticity of Retained Austenite in Bearing Steel

Conference · Fri Sep 01 00:00:00 EDT 2017

DOI:https://doi.org/10.1016/j.proeng.2017.10.968· OSTI ID:1410206

Bedekar, Vikram ^[1]; Voothaluru, Rohit ^[1]; Xie, Qingge  ^[2]; Stoica, Alexandru Dan  ^[2]; Hydea, R. Scott ^[1]; An, Ke  ^[2]

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1. Timken Technology Center
2. ORNL

The presence of retained austenite in bearing steels can have a significant effect on the mechanical response of the material at varying length scales. Since retained austenite is metastable and cannot be produced independently without martensite/carbides, the key physical data on elastic-plastic behaviour is absent. In order to address this issue, this study investigates the transformation behaviour of retained austenite using in-situ neutron diffraction during uniaxial tensile testing of through hardened A485 (Grade 1) bearing steel. The study showed that retained austenite does not transform until the yield point of 1.0 GPa, and the transformation suddenly initiates once the true stress exceeds the macroscopic yield point. Analysis of the lattice strain and evolution of peak intensities showed that most of the deformation is accommodated by the retained austenite with <200> crystallographic direction parallel to the loading direction (LD). Analysis further revealed that these austenite planes were transformed into martensite with <211> direction parallel with the LD.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1410206
• Resource Relation: Journal Volume: 207; Conference: International Conference on the Technology of Plasticity - Cambridge, , United Kingdom - 9/17/2017 12:00:00 AM-9/22/2017 12:00:00 AM
• Country of Publication: United States
• Language: English