Orientation dependence of the martensite transformation in a quenched and partitioned steel subjected to uniaxial tension

Abstract

The orientation dependence of the austenite-to-martensite transformation during uniaxial tensile testing was modelled using the phenomenological theory of martensite crystallography and the mechanical driving force. It was validated experimentally by means of electron backscatter diffraction measurements on a pre-defined zone of a quenched and partitioned steel during interrupted tensile tests. A close match is obtained between the predictions of the model and the experimental observations.

Effect of microstructure on fatigue behavior of advanced high strength steels produced by quenching and partitioning and the role of retained austenite

“…As it was already discussed above, some plastic deformation can be induced during fatigue testing with the high stress amplitudes into the RA microconstituent, as local stresses might reach and even exceed the RA yield stress [1,2,18,37,53]. It should be noted that these observations are in a very good accordance with those reported by De Knijf et al [52], who investigated the transformation rate of RA orientations during interrupted tensile testing of a Q&P steel. Their results on the distribution of the mechanical driving force for the martensitic transformation of RA are summarized in Fig.…”

“…8. According to [52], the cube orientation, which is frequently present in textures of fcc materials after conventional rolling and recrystallization annealing, shows the highest martensitic transformation potential. In contrast, typical fcc rolling components, such as the brass component, are less likely to undergo martensitic transformation than the recrystallization texture components and thus present lower transformation potential.…”

“…As an example, the orientation distribution functions (ODFs) in ϕ 2 = 0º, 45º and 65º sections of Euler space for RA in the QP-28 sample before and after fatigue testing [36,52] are presented in Fig. 7.…”

Texture formation in metal alloys with cubic crystal structures

“…Twinning provokes abrupt change of crystallographic orientation across the twinning plane, while the slip process induces crystal lattice rotation, which will bring the crystal in a position corresponding to the strain forced upon it, e.g. 4 Transformation potential versus the experimental transformation rate of 11 randomly chosen austenite orientations in a TRIP steel under tensile loading 19 6 Reconstructed austenite parent structure from EBSD scan of a product phase, finished rolled a below and b above the austenite Tnr temperature 32 5 Schematic representation of the process of texture memory. a two austenite grains with different KS relationships nucleating along a ferrite grain boundary, b the structure after complete transformation to austenite, c nucleation of a ferrite grain on cooling with YKS relationship to both neighbouring austenite grains, d final structure after displacive growth of the ferrite-the original grain orientation α 2 is restored 24 Kestens and Pirgazi Texture formation in metal alloys with cubic crystal structures Materials Science and Technology 2016 VOL 32 NO 13 in tension the active slip direction moves in the direction parallel to the tensile axis 32,33 (cf.…”

Effect of Q&P parameters on microstructure development and mechanical behaviour of Q&P steels

“…The major difference in the texture components of austenite between both samples is the presence of RC texture component in the 244-350-500 sample. The transformation potential of this component is between 0.05 and 0.08 with a minimum and maximum of 0.03 and 0.13 respectively (De Knijf et al, 2014b). A high transformation potential indicates low transformation stability related to the texture of the RA grain.…”