Deformation Behaviour of TRIP Steel Monitored by In Situ Neutron Diffraction

Abstract:

The paper presents results of in-situ neutron diffraction experiments aimed on monitoring the phase evolution and load distribution in transformation induced plasticity (TRIP) steel when subjected to tensile loading. Tensile deformation behaviour of two TRIP-assisted multiphase steel with slightly different microstructures resulted from different thermo-mechanical treatments applied was investigated by in-situ neutron diffraction. The steel with lower retained austenite volume fraction (f^γ=0.04) and higher volume fraction of needle-like bainite in the α-matrix exhibits higher yield stress (sample B, 600MPa) but considerably lower elongation in comparison to the steel with higher austenite volume fraction (f^γ=0.08), granular bainite and ferrite matrix (sample A, 500 MPa). The neutron diffraction results showed that the applied tensile load is redistributed at the yielding point in a way that the retained austenite bears a significantly larger load than the α-matrix during the TRIP steel deformation. Steel sample with higher volume fraction of retained austenite and less strong ferrite matrix proved to be a better TRIP steel with respect to strength, ductility and the side effect of the strain induced austenite-martensite transformation. The transforming retained austenite in time of loading provides potential for higher ductility of experimental TRIP steel but at the same time acts as a reinforcement phase during the further plastic deformation.TRIP steel, austenite conditioning, austenite transformation, structure, retained austenite, tensile deformation, neutron diffraction, load partitioning, mechanical properties.

• Periodical: Advanced Materials Research (Volume 939)
• Pages: 25-30
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.939.25
• Online since: May 2014
• Authors: Jozef Zrník*, Ondrej Muránsky, Petr Sittner
• Keywords: Austenite Conditioning, Austenite Transformation, Load Partitioning, Mechanical Property, Neutron Diffraction, Retained Austenite, Structure, Tensile Deformation, TRIP Steel

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