Shear and shuffling accomplishing polymorphic fcc γ → hcp ε → bct α martensitic phase transformation

Yang, Xu Sheng; Sun, Sheng; Ruan, Haihui; Shi, San-Qiang; Zhang, Tong‐Yi

doi:10.1016/j.actamat.2017.07.016

Cited by 87 publications

(21 citation statements)

References 34 publications

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“…5c and 5d at 5% thickness reduction. In agreement with previous observations [58][59][60][61], γ-ISFs in the γ phase nucleate εmartensite; which in turn coarsens laterally in the form of fine deformation-induced laths. The presence of an untransformed γ region in Fig.…”

Section: 1nucleation Of Deformation-induced ε-Martensite and Its Susupporting

confidence: 92%

Nucleation, coarsening and deformation accommodation mechanisms of ε-martensite in a high manganese steel

Pramanik

Gazder

Saleh

et al. 2018

Materials Science and Engineering: A

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Section: 1nucleation Of Deformation-induced ε-Martensite and Its Susupporting

confidence: 92%

Nucleation, coarsening and deformation accommodation mechanisms of ε-martensite in a high manganese steel

Pramanik

Gazder

Saleh

et al. 2018

Materials Science and Engineering: A

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“…In fact, there are three types of Shockley partials on each {111} FCC plane. Although it is not possible to differentiate stacking faults caused by the motion of all the three types of Shockley partials [31], the components of the Burgers vectors of these partials along 110 FCC direction are different. In addition to a single type of HCP stacking in Figures 3(d) and 4(a), two kinds of stacking sequences can coexist.…”

Section: Resultsmentioning

confidence: 99%

“…Based on the nature of FCC and HCP lattices, the HCP structure can be readily transformed locally from the FCC structure by introducing stacking faults [23,31]. Therefore, the SFE of materials, which represents the energy associated with interrupting the normal stacking sequence of a crystal plane [32], plays a significant role in the FCC-to-HCP transformation.…”

Section: Resultsmentioning

confidence: 99%

Cryogenic-deformation-induced phase transformation in an FeCoCrNi high-entropy alloy

Lin

Liu

et al. 2018

Materials Research Letters

174

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An FeCoCrNi high-entropy alloy (HEA) was deformed at ambient temperature and cryogenic temperatures down to 4.2 K. Phase transformation from a face-centered cubic (FCC) structure to a hexagonal close-packed (HCP) structure occurred during cryogenic deformation. Lowering the temperature promotes the transformation. Atomic-scale structural characterisation suggested that the formation of the HCP structure was achieved via the glide of Shockley partial dislocations on every other {111} FCC plane. Due to the kinetic limitation, the occurrence of this transformation was limited even though theoretical investigations predicted lower free energy of the HCP phase than that of the FCC phase in the HEA. IMPACT STATEMENT Atomic-scale FCC-to-HCP transformation was revealed in an FeCoCrNi high-entropy alloy during cryogenic-temperature deformation. The transformation was restricted due to the kinetic limitation.

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“…On the other hand, for a given medium, silicone oil, decreasing the grain size from 5 µm to about 0.01 µm increases the onset pressure from 6.9 to 12.3 GPa [35]. As the FCC to HCP martensitic transformation takes place by slip of 1/6 <112> partial dislocations on every second {111} plane [37], it is surprising, that in the present case under high shear stress, HPT at RT under a pressure of 7.8 GPa did not lead to the transformation. The reason may be the fast grain refinement into the nano range suppressing the transformation similar to deformation twinning [38].…”

Section: Microstructure Developmentmentioning

confidence: 99%

Microstructure, Texture, and Strength Development during High-Pressure Torsion of CrMnFeCoNi High-Entropy Alloy

et al. 2020

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The equiatomic face-centered cubic high-entropy alloy CrMnFeCoNi was severely deformed at room and liquid nitrogen temperature by high-pressure torsion up to shear strains of about 170. Its microstructure was analyzed by X-ray line profile analysis and transmission electron microscopy and its texture by X-ray microdiffraction. Microhardness measurements, after severe plastic deformation, were done at room temperature. It is shown that at a shear strain of about 20, a steady state grain size of 24 nm, and a dislocation density of the order of 1016 m−2 is reached. The dislocations are mainly screw-type with low dipole character. Mechanical twinning at room temperature is replaced by a martensitic phase transformation at 77 K. The texture developed at room temperature is typical for sheared face-centered cubic nanocrystalline metals, but it is extremely weak and becomes almost random after high-pressure torsion at 77 K. The strength of the nanocrystalline material produced by high-pressure torsion at 77 K is lower than that produced at room temperature. The results are discussed in terms of different mechanisms of deformation, including dislocation generation and propagation, twinning, grain boundary sliding, and phase transformation.

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Shear and shuffling accomplishing polymorphic fcc γ → hcp ε → bct α martensitic phase transformation

Cited by 87 publications

References 34 publications

Nucleation, coarsening and deformation accommodation mechanisms of ε-martensite in a high manganese steel

Nucleation, coarsening and deformation accommodation mechanisms of ε-martensite in a high manganese steel

Cryogenic-deformation-induced phase transformation in an FeCoCrNi high-entropy alloy

Microstructure, Texture, and Strength Development during High-Pressure Torsion of CrMnFeCoNi High-Entropy Alloy

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